LiNa₃(SO₄)₂·6H₂O: a lithium double salt causing trouble in the industrial conversion of Li₂SO₄ into LiOH

The crystal structure of LiNa₃(SO₄)₂·6H₂O is discussed. In the context of the production of LiOH for batteries, the formation of the double salt should be avoided. Detection of its presence by means of XRD is important.

Abstract

Lithium tris­odium bis­(sulfate) hexa­hydrate, LiNa₃(SO₄)₂·6H₂O was crystallized from aqueous solution at 298 K and the structure solved at different temperatures between 90 and 293 K. The structure is isomorphic with the corresponding molybdate and selenate double salt hydrate. It belongs to the non-centrosymmetric trigonal space group R3c (161). The temperature dependence of the lattice parameters has been determined. Further characterization by powder XRD and thermal analysis is reported.

Chemical context  

In the presently preferred process of LiOH production for batteries, an aqueous Li₂SO₄ solution is reacted with NaOH at temperatures well below 273 K (mostly at 268 K) for separating sodium sulfate in the form of its deca­hydrate (Glauber salt) according to the equation

Li₂SO_4(aq) + 2 NaOH_(aq) → 2 LiOH_(aq) + Na₂SO₄·10H₂O_(s)

The sodium sulfate hydrate is removed and from the remaining solution, water is evaporated to crystallize LiOH·H₂O. However, during cooling the solution from ambient temperature, the solution passes the stability field of LiNa₃(SO₄)₂·6H₂O, which extends from 271.3 to 321 K (Sohr et al., 2017 ▸). Once formed, it will not disappear on further cooling. Rapid and reliable detection of its presence or absence by means of XRD is important. A powder diffraction pattern is available from the PDF database (Powder Diffraction File 33-1258, Inter­national Center for Diffraction Data), but no conclusive comment is attached regarding the conditions under which the material was obtained and prepared for powder XRD. It is known that the material loses its water of crystallization very easily. Therefore, in their careful thermodynamic study of the system Li₂SO₄–Na₂SO₄–H₂O at 298 K, Filippov & Kalinkin (1989 ▸) did not make an attempt to isolate the double salt hydrate because of instability. Ji et al. (2015 ▸) include a figure of the PXRD pattern, but only in a mixture with anhydrous LiNaSO₄. The growth of crystals under defined conditions and deriving the PXRD pattern from single-crystal structure analysis could resolve doubts about the PXRD pattern.

LiNa₃(SO₄)₂·6H₂O was first crystallized by Mitscherlich (1843 ▸) and later, preparative conditions were specified (Scacchi, 1867 ▸). Early crystallographic characterization is summarized by Groth (1908 ▸), where the cited paper of Traube (1894 ▸) is of particular inter­est, since he determined the correct polar point group 3m for this compound and the isomorphic compounds LiNa₃(MO₄)₂·6H₂O with M = S, Se, Mo, Cr. Even a mixed compound LiNa₃{(SO₄)_0.5(CrO₄)_0.5} was described within this series. A first crystal structure of the molybdate was published by Klevtsova et al. (1988 ▸). Later, Kaminskii and co-workers grew large crystals of the molybdate (Kaminskii et al., 2009 ▸) and selenate (Kaminskii et al., 2007 ▸) for studies on the non-linear optical effects of the materials, where they also re-determined and refined the crystal structures at ambient temperature, but without discussion of structural details.

Structural commentary  

Single-crystal structure determination was performed at five temperatures between 90 and 293 K. At all temperatures, the structure could be solved in the polar space group R3c H (161). The cell parameters varied continuously with temperature (Table 1 ▸ and Fig. 1 ▸). Thus, the results confirm the isomorphism to the molybdate LiNa₃(MoO₄)₂·6H₂O (Kaminskii et al., 2009 ▸) and no structural change within the investigated temperature range. Fig. 2 ▸ shows the asymmetric unit completed with atoms to visualize the coordination of sodium, lithium and sulfur. There is only one crystallographically distinguishable sodium and lithium position, but two for sulfur. Sodium is surrounded by six oxygen atoms, three belong to water mol­ecules (blue) and the remaining three to sulfate groups. The distance of 2.639 Å between Na1 and O4 is quite long. Also, the angle O1—Na1—O4 of 165° deviates considerably from 180°. However, in a first approximation the environment of sodium atoms can be described as a distorted octa­hedron. The water mol­ecules with O6 bridge three sodium ions to a trimeric unit as shown in Fig. 3 ▸. The trimers look like cyclo­hexane rings (Fig. 3 ▸ b) in a chair conformation with the water mol­ecules on the upper three points (Fig. 3 ▸ c).

Table 1. Hydrogen-bond geometry (Å, °) at 273 K.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O6—H6A⋯O2i	0.77 (5)	2.00 (5)	2.764 (11)	170 (5)
O6—H6B⋯O1	0.83 (4)	2.15 (4)	2.937 (7)	157 (4)
O5—H5B⋯O1ii	0.79 (4)	1.92 (4)	2.694 (7)	165 (4)
O5—H5A⋯O2iii	0.89 (4)	1.97 (4)	2.828 (6)	163 (3)

Symmetry codes: (i) -y+{\script{1\over 3}}, -x+{\script{2\over 3}}, z+{\script{1\over 6}}; (ii) x-{\script{1\over 3}}, x-y+{\script{1\over 3}}, z-{\script{1\over 6}}; (iii) -x+y, -x+1, z.

Figure 1.

Variation of lattice parameters with temperature; a axis in red, c axis in blue, values divided by four, volume shown in black; circles: from single-crystal measurements, stars: data from powder X-ray measurement: a = 8.4552 (7) Å, c = 30.3032 (3) Å, V = 1876.18 Å.

Figure 2.

Asymmetric unit plus bonds. Ellipsoids are drawn at the 50% level. Symmetry codes: (I) 1 − y, 1 + x − y, z; (II) −y − y, 1 − x, z; (III) − − x + y, − + y, −1/6 +) ; (IV) −x + y, −x, z; (V) 1 − y, x − y, z; (VI) 1 − x + y, 1 − x, z; (VII)  − x + y, − + y,  + z; (VIII) 4/3 − y,  − x,  + z; (IX)  + x,  + x − y,  + z.

Figure 3.

The trimeric unit Na₃(H₂O)₃ viewing from different directions (a, b and c).

The lithium cation is coordinated by three water mol­ecules (O5) and the apex (O3) of a sulfate anion containing S1 completes a tetra­hedron (Fig. 2 ▸). Thus, the trimeric Na₃(H₂O)₃ and the double tetra­hedron Li(H₂O)₃(SO₄) form the characteristic structural units of this compound. In Fig. 4 ▸, the arrangement of these units is shown within the unit cell separately for Na₃(H₂O)₃ (Fig. 4 ▸ a) and Li(H₂O)₃(SO₄) (Fig. 4 ▸ b). In Fig. 4 ▸ b the sulfate anions with S2 are added as darker colored tetra­hedra. The repeat unit requires stacking of six such units along the c-axis direction. The uniform orientation of the units underlines the polar character of the c axis.

Figure 4.

Stacking of (a) the trimeric Na₃(H₂O)₃ and (b) the Li(H₂O)₃(SO₄) units along the c axis within a unit cell. Additional SO₄ groups with the S2 sulfur atom are shown (dark yellow).

Supra­molecular features  

The overall structure of the compound is polymeric with water and sulfate anions connecting the cations. The three water mol­ecules coordinated at the lithium cation are at the same time coordinated to three sodium cations, each sodium ion belonging to another trimeric sodium ring forming a water–cation coordination network, as shown in Fig. 5 ▸. When including the entire coordination spheres of sodium, one can describe the trimers as edge-bridged octa­hedra, as illustrated in Fig. 6 ▸ a and 6b. Thereby, the O4 oxygen from the sulfate anion of S2 represents a common coordination point from below (Fig. 6 ▸ a). The height of sulfur S1 along the c axis is near that of Na1. Thus, the three corners of this sulfate tetra­hedron connect three trimeric units within a sodium ion layer, as shown in Fig. 7 ▸ from two viewing angles. As shown in Fig. 6 ▸, the sulfate with S2 is positioned with its oxygen atom (O4) at the center below the trimeric units, and thus the other three O1 atoms of this sulfate anion connect three trimeric sodium units from the adjacent layer below (Fig. 8 ▸). In this way, the sulfate with S2 acts as a connector between sodium layers and the sulfate with S1 within one layer. Additional inter­connections between layers are realized by the sulfate of S1 as part of the double tetra­hedron Li(H₂O)₃(SO₄), as illustrated in Fig. 9 ▸.

Figure 5.

Cation–water coordination network within the ab plane. Sodium = gray, oxygen = blue, lithium = pink, hydrogen = white.

Figure 6.

Representation of the sodium ion coordination within a trimeric unit: (a) stick and ball, (b) polyhedrons.

Figure 7.

Inter­connection of trimeric units within one layer by sulfate tetra­hedra with the S1 sulfur atom viewed from two directions (a and b).

Figure 8.

Inter­connections of sodium layers by sulfate tetra­hedra with the S2 sulfur atom (dark yellow).

Figure 9.

Inter­connections of sodium layers by sulfate tetra­hedra with the S2 sulfur atom (dark yellow).

Investigation of the hydrogen-bond network (Table 1 ▸) revealed that, inter­estingly, the water mol­ecules form hydrogen bonds only to the sulfate groups, but not between themselves as is observed in a channel-like arrangement in Li₂SO₄·H₂O (Fig. 10 ▸). However, as can be seen from Fig. 11 ▸, the hydrogen atoms H1 and H3 share O1 as a common acceptor atom of the sulfate with S1, and H2 and H4 do the same with O2 at the sulfate anion of S2. The bond lengths vary between 1.92 and 2.15 Å. Fig. 12 ▸ shows a larger part of the hydrogen-bond network, projected both along the c axis (Fig. 12 ▸ a) and perpendicular to the c axis (Fig. 12 ▸ b). From the latter, it can be recognized that the hydrogen bonds contribute to the bonding strength within a layer, but not between the layers. Connections between the layers are established by cation–anion coordination as shown in Figs. 8 ▸ and 9 ▸.

Figure 10.

Hydrogen-bonded (blue bonds) chain of water mol­ecules along the b-axis direction in the structure of Li₂SO₄·H₂O (Fugel et al., 2019 ▸)

Figure 11.

Hydrogen bonds from water mol­ecules to the S1 and S2 sulfate groups.

Figure 12.

Larger part of the hydrogen-bond network projected on (a) the ab plane and (b) the ac plane.

Database survey  

In the Inorganic Crystal Structure Database (ICSD), only 1164 records with space group R3c (No. 161) can be found. Most of them belong to the LiNbO₃ or Whitlockite type [Whitlockite = MgCa₉(PO₄)₆(HPO₄)]. Compounds containing lithium in this space group numbered 179, of which 148 belong again to LiNbO₃ type. The isomorphic molybdate (ICSD col 65006, col 420160) represents a structure type of its own. The isomorphic selenate LiNa₃(SeO₄)₂·6H₂O (Kaminskii et al. 2007 ▸) could not be found in the ICSD. Inter­estingly, the mineral chlorartinite, Mg₂[Cl(OH)CO₃]·2H₂O, which forms easily in MgO-based building materials, also crystallizes in the space group R3c (Sugimoto et al., 2006 ▸).

Synthesis, crystallization and characterization  

Single crystals were grown from about 120 mL of an aqueous solution containing Li₂SO₄ and Na₂SO₄ in a molar ratio of approx. 1:1 and an absolute concentration well below the solubility line (Fig. 13 ▸). The solution was kept in an desiccator with 50% H₂SO₄ solution as drying agent. Over two weeks, a number of crystals with sizes of 1–7 mm were formed that showed the typical trigonal–pyramidal form. Small pieces were cut for XRD measurements. The density of 1.995 g cm⁻³ calculated from the parameters at 293 K (Table 1 ▸) is in excellent agreement with the experimental value of 2.009 g cm⁻³ as cited in Groth (1908 ▸).

Figure 13.

Solubility data in the system Li₂SO₄–Na₂SO₄–H₂O at 298 K (Sohr et al., 2017 ▸). Crystallization points of LiNa₃(SO₄)₂·6H₂O are shown in red.

Attempts were made to record powder XRD patterns from quickly ground crystals. Large crystals appear stable at least for some minutes on a filter paper. However, when grinding to achieve a crystal powder, dehydration took place. In cases of less intensive grinding, the texture effects were too large for a representative powder XRD pattern. Thus, particularly for powder XRD measurements, a suspension of fine crystals was prepared: To a 2 molar solution of Na₂SO₄, an equivalent amount of anhydrous Li₂SO₄ was added. The suspension was stirred two days at 298 K. The supernatant solution was deca­nted and subsequently some slurry was transferred into the expanded, upper part of a Hilgenberg glass capillary. By means of a centrifuge (30 minutes at 4000 r.p.m.), the crystals were pressed into the capillary. This way the available capillary volume was effectively filled with crystals (Fig. 14 ▸). A PXRD pattern obtained under rotation is shown in Fig. 15 ▸ in comparison with the one calculated from the crystal structure.

Figure 14.

Image of a Hilgenberg capillary (diameter 0.5 mm) filled with crystals of LiNa₃(SO₄)₂·6H₂O by means of centrifugal compaction.

Figure 15.

Powder XRD pattern of LiNa₃(SO₄)₂·6H₂O recorded from a rotating capillary. Scan rate: 20 sec, steps 0.023°. For comparison, the calculated powder pattern from structural data at 293 K is also shown.

The powder pattern was measured at room temperature on a Bruker D8 Discover diffractometer in Bragg–Brentano geometry with Cu Kα radiation (λ = 1.5406 Å) and a linear detector Våntec-1 (geometry angle 1°). The measurements were made with a Göbel mirror as monochromator with a 1.0 mm slit and a 2.5° primary soller. The generator was set to 40 kV/40 mA. The program TOPAS 5.0 (Bruker, 2009 ▸) was used to refine the lattice parameters (Fig. 1 ▸). The solved structure from single crystal XRD at 293K was used as starting point of the refinement.

Thermal analyses (Fig. 16 ▸) were performed from roughly crushed, large single crystals. Water is released in one step below 353 K. The mass loss of 29.2% is near the theoretical value of 28.7%. In a second experiment, the measured value was 29.1%.

Figure 16.

Thermal analysis of LiNa₃(SO₄)₂·6H₂O. Heating rate: 5 K min⁻¹; N₂ purge: 300 ml min⁻¹.

Refinement  

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. Structure solution using direct methods and a refinement of the atomic positions with respect to the isotropic displacement parameters led to the positions of the Na, Li, S and O atoms. The positions of the H atoms could be located from residual electron-density maxima after further refinement. H atoms were refined isotropically.

Table 2. Experimental details.

	90 K	180 K	260 K	273 K	293 K
Crystal data
Chemical formula	LiNa3(SO4)2·6H2O	LiNa3(SO4)2·6H2O	LiNa3(SO4)2·6H2O	LiNa3(SO4)2·6H2O	LiNa3(SO4)2·6H2O
M r	376.13	376.13	376.13	376.13	376.13
Crystal system, space group	Trigonal, R3c:H	Trigonal, R3c:H	Trigonal, R3c:H	Trigonal, R3c:H	Trigonal, R3c:H
a, c (Å)	8.3876 (13), 30.048 (7)	8.4006 (19), 30.111 (9)	8.426 (2), 30.197 (4)	8.4337 (17), 30.235 (6)	8.457 (7), 30.33 (3)
V (Å3)	1830.7 (7)	1840.3 (10)	1856.6 (10)	1862.4 (8)	1879 (4)
Z	6	6	6	6	6
Radiation type	Mo Kα	Mo Kα	Mo Kα	Mo Kα	Mo Kα
μ (mm−1)	0.62	0.61	0.61	0.61	0.60
Crystal size (mm)	0.3 × 0.15 × 0.1	0.3 × 0.15 × 0.1	0.3 × 0.15 × 0.1	0.3 × 0.15 × 0.1	0.3 × 0.15 × 0.1
Data collection
Diffractometer	Stoe IPDS 2	Stoe IPDS 2	Stoe IPDS 2	Stoe IPDS 2	Stoe IPDS 2T
Absorption correction	Integration Coppens (1970 ▸)	Integration Coppens (1970 ▸)	Integration Coppens (1970 ▸)	Integration Coppens (1970 ▸)	Integration Coppens (1970 ▸)
Tmin, Tmax	0.924, 0.945	0.682, 0.941	0.864, 0.938	0.773, 0.866	0.517, 0.844
No. of measured, independent and observed [I > 2σ(I)] reflections	12154, 1089, 1089	4345, 1088, 1087	5068, 915, 906	8584, 1159, 1141	1376, 730, 695
R int	0.027	0.035	0.034	0.035	0.054
(sin θ/λ)max (Å−1)	0.685	0.692	0.643	0.694	0.641
Refinement
R[F2 > 2σ(F 2)], wR(F 2), S	0.013, 0.036, 1.14	0.021, 0.053, 1.18	0.017, 0.043, 1.13	0.019, 0.053, 1.28	0.038, 0.105, 1.11
No. of reflections	1089	1088	915	1159	730
No. of parameters	78	78	78	77	78
No. of restraints	5	1	1	1	5
H-atom treatment	All H-atom parameters refined	All H-atom parameters refined	All H-atom parameters refined	All H-atom parameters refined	All H-atom parameters refined
Δρmax, Δρmin (e Å−3)	0.16, −0.18	0.23, −0.33	0.14, −0.20	0.19, −0.33	0.33, −0.47
Absolute structure	Flack x determined using 539 quotients [(I +)−(I −)]/[(I +)+(I −)] (Parsons et al., 2013 ▸)	Classical Flack method preferred over Parsons because s.u. lower	Flack x determined using 437 quotients [(I +)−(I −)]/[(I +)+(I −)] (Parsons et al., 2013 ▸)	Flack x determined using 551 quotients [(I +)−(I −)]/[(I +)+(I −)] (Parsons et al., 2013 ▸)	Classical Flack method preferred over Parsons because s.u. lower
Absolute structure parameter	0.01 (3)	−0.08 (10)	−0.04 (6)	0.04 (4)	−0.3 (3)

Computer programs: X-AREA and X-RED (Stoe & Cie, 2015 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2018/3 (Sheldrick, 2015 ▸), DIAMOND (Brandenburg, 2017 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

CCDC references: 2101588, 2101587, 2101586, 2101585, 2101584

Additional supporting information: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Crystal data

LiNa3(SO4)2·6H2O	Dx = 2.047 Mg m−3
Mr = 376.13	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c:H	Cell parameters from 2749 reflections
a = 8.3876 (13) Å	θ = 25.0–27.5°
c = 30.048 (7) Å	µ = 0.62 mm−1
V = 1830.7 (7) Å3	T = 90 K
Z = 6	Needle, colourless
F(000) = 1152	0.3 × 0.15 × 0.1 mm

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Data collection

Stoe IPDS 2 diffractometer	1089 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	1089 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.027
Detector resolution: 6.67 pixels mm-1	θmax = 29.1°, θmin = 3.1°
rotation method scans	h = −10→11
Absorption correction: integration Coppens (1970)	k = −11→11
Tmin = 0.924, Tmax = 0.945	l = −40→40
12154 measured reflections

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Refinement

Refinement on F2	All H-atom parameters refined
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0238P)2 + 0.6042P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.013	(Δ/σ)max < 0.001
wR(F2) = 0.036	Δρmax = 0.16 e Å−3
S = 1.14	Δρmin = −0.18 e Å−3
1089 reflections	Extinction correction: SHELXL2018/3 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
78 parameters	Extinction coefficient: 0.0037 (7)
5 restraints	Absolute structure: Flack x determined using 539 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Hydrogen site location: difference Fourier map	Absolute structure parameter: 0.01 (3)

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Li1	0.666667	0.333333	0.15432 (13)	0.0085 (7)
Na1	0.23426 (7)	0.26504 (7)	0.06063 (2)	0.00705 (14)
S1	0.666667	0.333333	0.04323 (2)	0.00332 (12)
S2	0.333333	0.666667	0.12552 (2)	0.00325 (12)
O1	0.39254 (13)	0.53800 (12)	0.10892 (3)	0.00609 (18)
O2	0.51766 (12)	0.36335 (12)	0.02615 (3)	0.00667 (18)
O3	0.666667	0.333333	0.09154 (6)	0.0095 (4)
O4	0.333333	0.666667	0.17470 (6)	0.0067 (3)
O5	0.14513 (13)	0.42897 (12)	0.01016 (3)	0.00656 (17)
H5A	0.053 (2)	0.429 (3)	0.0194 (7)	0.016 (5)*
H5B	0.106 (3)	0.363 (3)	−0.0120 (6)	0.020 (5)*
O6	−0.02932 (13)	0.20979 (13)	0.10180 (3)	0.00744 (19)
H6B	−0.007 (3)	0.316 (2)	0.1019 (8)	0.017 (5)*
H6A	−0.022 (3)	0.190 (3)	0.1279 (5)	0.017 (5)*

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Li1	0.0089 (10)	0.0089 (10)	0.0078 (16)	0.0044 (5)	0.000	0.000
Na1	0.0065 (2)	0.0076 (2)	0.0072 (2)	0.00369 (19)	0.00175 (17)	0.00177 (18)
S1	0.00352 (15)	0.00352 (15)	0.0029 (2)	0.00176 (8)	0.000	0.000
S2	0.00334 (15)	0.00334 (15)	0.0031 (2)	0.00167 (8)	0.000	0.000
O1	0.0066 (4)	0.0060 (4)	0.0074 (4)	0.0045 (3)	−0.0002 (3)	−0.0015 (3)
O2	0.0057 (4)	0.0084 (4)	0.0079 (4)	0.0050 (3)	−0.0001 (3)	0.0013 (3)
O3	0.0129 (5)	0.0129 (5)	0.0028 (8)	0.0065 (3)	0.000	0.000
O4	0.0085 (5)	0.0085 (5)	0.0031 (7)	0.0042 (2)	0.000	0.000
O5	0.0063 (4)	0.0067 (4)	0.0068 (4)	0.0034 (3)	0.0010 (3)	−0.0010 (3)
O6	0.0089 (4)	0.0068 (4)	0.0064 (4)	0.0038 (4)	0.0000 (3)	0.0003 (3)

Lithium trisodium bis(sulfate) hexahydrate (Na3_Li_2SO4_6H2O-90K). Geometric parameters (Å, º)

Li1—O3	1.886 (4)	Na1—O4v	2.6330 (14)
Li1—O5i	1.9434 (17)	Na1—Na1vi	3.6475 (10)
Li1—O5ii	1.9435 (17)	Na1—Na1iv	3.6475 (10)
Li1—O5iii	1.9435 (17)	S1—O3	1.4515 (17)
Li1—Na1i	3.748 (2)	S1—O2vii	1.4844 (9)
Li1—Na1iii	3.748 (2)	S1—O2	1.4844 (9)
Li1—Na1ii	3.748 (2)	S1—O2viii	1.4844 (9)
Na1—O2	2.3331 (10)	S2—O4	1.4777 (17)
Na1—O6iv	2.3498 (11)	S2—O1ix	1.4818 (9)
Na1—O6	2.3682 (11)	S2—O1	1.4818 (9)
Na1—O5	2.4036 (11)	S2—O1x	1.4818 (9)
Na1—O1	2.4638 (10)
O3—Li1—O5i	110.37 (11)	O1—Na1—Na1vi	122.28 (3)
O3—Li1—O5ii	110.36 (11)	O4v—Na1—Na1vi	46.16 (3)
O5i—Li1—O5ii	108.56 (12)	O2—Na1—Na1iv	102.41 (3)
O3—Li1—O5iii	110.36 (11)	O6iv—Na1—Na1iv	39.55 (3)
O5i—Li1—O5iii	108.56 (12)	O6—Na1—Na1iv	85.42 (3)
O5ii—Li1—O5iii	108.56 (12)	O5—Na1—Na1iv	123.78 (3)
O3—Li1—Na1i	125.81 (5)	O1—Na1—Na1iv	142.40 (2)
O5i—Li1—Na1i	34.21 (6)	O4v—Na1—Na1iv	46.16 (3)
O5ii—Li1—Na1i	74.41 (8)	Na1vi—Na1—Na1iv	60.0
O5iii—Li1—Na1i	119.02 (15)	O2—Na1—Li1xi	72.17 (3)
O3—Li1—Na1iii	125.81 (5)	O6iv—Na1—Li1xi	167.14 (3)
O5i—Li1—Na1iii	74.40 (8)	O6—Na1—Li1xi	104.31 (4)
O5ii—Li1—Na1iii	119.01 (15)	O5—Na1—Li1xi	27.04 (3)
O5iii—Li1—Na1iii	34.21 (6)	O1—Na1—Li1xi	74.64 (5)
Na1i—Li1—Na1iii	89.23 (7)	O4v—Na1—Li1xi	98.29 (5)
O3—Li1—Na1ii	125.81 (5)	Na1vi—Na1—Li1xi	105.94 (2)
O5i—Li1—Na1ii	119.02 (15)	Na1iv—Na1—Li1xi	142.95 (5)
O5ii—Li1—Na1ii	34.21 (6)	O3—S1—O2vii	110.23 (4)
O5iii—Li1—Na1ii	74.40 (8)	O3—S1—O2	110.23 (4)
Na1i—Li1—Na1ii	89.23 (7)	O2vii—S1—O2	108.71 (5)
Na1iii—Li1—Na1ii	89.23 (7)	O3—S1—O2viii	110.23 (4)
O2—Na1—O6iv	95.05 (4)	O2vii—S1—O2viii	108.70 (5)
O2—Na1—O6	170.96 (4)	O2—S1—O2viii	108.71 (5)
O6iv—Na1—O6	88.14 (5)	O4—S2—O1ix	109.66 (4)
O2—Na1—O5	94.07 (4)	O4—S2—O1	109.66 (4)
O6iv—Na1—O5	162.69 (4)	O1ix—S2—O1	109.28 (4)
O6—Na1—O5	85.10 (4)	O4—S2—O1x	109.66 (4)
O2—Na1—O1	87.29 (4)	O1ix—S2—O1x	109.28 (4)
O6iv—Na1—O1	104.11 (4)	O1—S2—O1x	109.28 (4)
O6—Na1—O1	83.73 (3)	S2—O1—Na1	130.83 (5)
O5—Na1—O1	90.99 (3)	S1—O2—Na1	125.59 (6)
O2—Na1—O4v	103.31 (4)	S1—O3—Li1	180.0
O6iv—Na1—O4v	85.71 (4)	S2—O4—Na1xii	126.89 (4)
O6—Na1—O4v	85.34 (4)	S2—O4—Na1xiii	126.89 (4)
O5—Na1—O4v	77.88 (4)	Na1xii—O4—Na1xiii	87.68 (5)
O1—Na1—O4v	165.02 (3)	S2—O4—Na1i	126.89 (4)
O2—Na1—Na1vi	149.40 (3)	Na1xii—O4—Na1i	87.68 (5)
O6iv—Na1—Na1vi	85.68 (3)	Na1xiii—O4—Na1i	87.68 (5)
O6—Na1—Na1vi	39.18 (3)	Li1xi—O5—Na1	118.75 (8)
O5—Na1—Na1vi	79.01 (3)	Na1vi—O6—Na1	101.27 (4)

Symmetry codes: (i) x+1/3, x−y+2/3, z+1/6; (ii) −y+4/3, −x+2/3, z+1/6; (iii) −x+y+1/3, y−1/3, z+1/6; (iv) −x+y, −x, z; (v) −y+2/3, −x+1/3, z−1/6; (vi) −y, x−y, z; (vii) −x+y+1, −x+1, z; (viii) −y+1, x−y, z; (ix) −y+1, x−y+1, z; (x) −x+y, −x+1, z; (xi) −y+2/3, −x+4/3, z−1/6; (xii) −x+y+1/3, y+2/3, z+1/6; (xiii) −y+1/3, −x+2/3, z+1/6.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Crystal data

3(Na)Li2(SO4)6(H2O)	Dx = 2.036 Mg m−3
Mr = 376.13	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c:H	Cell parameters from 7724 reflections
a = 8.4006 (19) Å	θ = 2.8–30.0°
c = 30.111 (9) Å	µ = 0.61 mm−1
V = 1840.3 (10) Å3	T = 180 K
Z = 6	Needle, colourless
F(000) = 1152	0.3 × 0.15 × 0.1 mm

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Data collection

Stoe IPDS 2 diffractometer	1088 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	1087 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.035
Detector resolution: 6.67 pixels mm-1	θmax = 29.5°, θmin = 3.1°
rotation method scans	h = −11→11
Absorption correction: integration Coppens (1970)	k = −11→11
Tmin = 0.682, Tmax = 0.941	l = −40→40
4345 measured reflections

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Refinement

Refinement on F2	All H-atom parameters refined
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0413P)2] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.021	(Δ/σ)max < 0.001
wR(F2) = 0.053	Δρmax = 0.23 e Å−3
S = 1.18	Δρmin = −0.33 e Å−3
1088 reflections	Extinction correction: SHELXL2018/3 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
78 parameters	Extinction coefficient: 0.055 (4)
1 restraint	Absolute structure: Classical Flack method preferred over Parsons because s.u. lower
Hydrogen site location: difference Fourier map	Absolute structure parameter: −0.08 (10)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Li1	0.666667	0.333333	0.15397 (15)	0.0112 (7)
Na1	0.23455 (8)	0.26585 (8)	0.06065 (3)	0.0123 (2)
S1	0.666667	0.333333	0.04314 (2)	0.00567 (18)
S2	0.333333	0.666667	0.12563 (2)	0.00580 (18)
O1	0.39232 (16)	0.53835 (14)	0.10903 (4)	0.0101 (2)
O2	0.51801 (14)	0.36299 (14)	0.02615 (4)	0.0116 (2)
O3	0.666667	0.333333	0.09124 (10)	0.0182 (6)
O4	0.333333	0.666667	0.17460 (9)	0.0113 (5)
O5	0.14543 (15)	0.42931 (14)	0.00995 (4)	0.0107 (2)
H5A	0.057 (4)	0.431 (3)	0.0205 (10)	0.019 (6)*
H5B	0.106 (4)	0.359 (4)	−0.0106 (11)	0.021 (5)*
O6	−0.02970 (15)	0.20921 (15)	0.10179 (4)	0.0125 (2)
H6B	−0.011 (4)	0.311 (5)	0.1015 (12)	0.029 (8)*
H6A	−0.023 (4)	0.189 (4)	0.1275 (11)	0.019 (6)*

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Li1	0.0125 (11)	0.0125 (11)	0.0087 (17)	0.0062 (5)	0.000	0.000
Na1	0.0118 (3)	0.0139 (3)	0.0119 (3)	0.0068 (2)	0.00347 (19)	0.00357 (19)
S1	0.0068 (2)	0.0068 (2)	0.0033 (3)	0.00342 (11)	0.000	0.000
S2	0.0064 (2)	0.0064 (2)	0.0046 (3)	0.00320 (11)	0.000	0.000
O1	0.0119 (4)	0.0099 (4)	0.0107 (5)	0.0073 (3)	−0.0002 (3)	−0.0020 (3)
O2	0.0095 (4)	0.0153 (5)	0.0131 (4)	0.0085 (4)	0.0002 (3)	0.0022 (3)
O3	0.0253 (9)	0.0253 (9)	0.0039 (11)	0.0127 (4)	0.000	0.000
O4	0.0143 (7)	0.0143 (7)	0.0054 (11)	0.0071 (4)	0.000	0.000
O5	0.0117 (4)	0.0099 (4)	0.0103 (5)	0.0051 (3)	0.0010 (4)	−0.0011 (3)
O6	0.0150 (5)	0.0122 (5)	0.0096 (5)	0.0064 (4)	0.0007 (3)	0.0000 (4)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-180K). Geometric parameters (Å, º)

Li1—O3	1.889 (6)	Na1—O4v	2.644 (2)
Li1—O5i	1.9454 (19)	Na1—Na1iv	3.6617 (13)
Li1—O5ii	1.9455 (19)	Na1—Na1vi	3.6618 (13)
Li1—O5iii	1.9455 (19)	S1—O3	1.448 (3)
Li1—Na1ii	3.756 (3)	S1—O2	1.4813 (11)
Li1—Na1iii	3.756 (3)	S1—O2vii	1.4814 (11)
Li1—Na1i	3.756 (3)	S1—O2viii	1.4814 (11)
Na1—O2	2.3393 (12)	S2—O4	1.474 (3)
Na1—O6iv	2.3546 (13)	S2—O1	1.4804 (11)
Na1—O6	2.3734 (13)	S2—O1ix	1.4804 (11)
Na1—O5	2.4093 (13)	S2—O1x	1.4804 (11)
Na1—O1	2.4669 (12)
O3—Li1—O5i	110.52 (13)	O1—Na1—Na1iv	142.29 (3)
O3—Li1—O5ii	110.52 (13)	O4v—Na1—Na1iv	46.17 (4)
O5i—Li1—O5ii	108.41 (13)	O2—Na1—Na1vi	149.23 (3)
O3—Li1—O5iii	110.52 (13)	O6iv—Na1—Na1vi	85.51 (3)
O5i—Li1—O5iii	108.41 (13)	O6—Na1—Na1vi	39.06 (3)
O5ii—Li1—O5iii	108.40 (13)	O5—Na1—Na1vi	79.08 (3)
O3—Li1—Na1ii	126.01 (6)	O1—Na1—Na1vi	122.25 (3)
O5i—Li1—Na1ii	118.70 (17)	O4v—Na1—Na1vi	46.17 (4)
O5ii—Li1—Na1ii	34.19 (6)	Na1iv—Na1—Na1vi	60.0
O5iii—Li1—Na1ii	74.26 (9)	O2—Na1—Li1xi	72.31 (3)
O3—Li1—Na1iii	126.01 (6)	O6iv—Na1—Li1xi	167.18 (4)
O5i—Li1—Na1iii	74.26 (9)	O6—Na1—Li1xi	104.59 (4)
O5ii—Li1—Na1iii	118.70 (17)	O5—Na1—Li1xi	26.99 (3)
O5iii—Li1—Na1iii	34.19 (6)	O1—Na1—Li1xi	74.93 (6)
Na1ii—Li1—Na1iii	88.94 (8)	O4v—Na1—Li1xi	98.14 (7)
O3—Li1—Na1i	126.01 (6)	Na1iv—Na1—Li1xi	142.78 (5)
O5i—Li1—Na1i	34.19 (6)	Na1vi—Na1—Li1xi	105.95 (2)
O5ii—Li1—Na1i	74.27 (9)	O3—S1—O2	110.20 (6)
O5iii—Li1—Na1i	118.70 (17)	O3—S1—O2vii	110.21 (6)
Na1ii—Li1—Na1i	88.94 (8)	O2—S1—O2vii	108.73 (6)
Na1iii—Li1—Na1i	88.94 (8)	O3—S1—O2viii	110.21 (6)
O2—Na1—O6iv	94.92 (4)	O2—S1—O2viii	108.73 (6)
O2—Na1—O6	171.37 (5)	O2vii—S1—O2viii	108.73 (6)
O6iv—Na1—O6	87.90 (6)	O4—S2—O1	109.74 (6)
O2—Na1—O5	94.13 (4)	O4—S2—O1ix	109.74 (6)
O6iv—Na1—O5	162.50 (5)	O1—S2—O1ix	109.20 (6)
O6—Na1—O5	85.35 (5)	O4—S2—O1x	109.74 (6)
O2—Na1—O1	87.57 (4)	O1—S2—O1x	109.20 (6)
O6iv—Na1—O1	104.10 (4)	O1ix—S2—O1x	109.20 (6)
O6—Na1—O1	83.82 (4)	S2—O1—Na1	130.92 (7)
O5—Na1—O1	91.21 (4)	S1—O2—Na1	125.78 (7)
O2—Na1—O4v	103.11 (6)	S1—O3—Li1	180.0
O6iv—Na1—O4v	85.59 (5)	S2—O4—Na1xii	126.90 (6)
O6—Na1—O4v	85.22 (5)	S2—O4—Na1xiii	126.90 (6)
O5—Na1—O4v	77.78 (5)	Na1xii—O4—Na1xiii	87.67 (9)
O1—Na1—O4v	165.06 (3)	S2—O4—Na1i	126.90 (6)
O2—Na1—Na1iv	102.10 (4)	Na1xii—O4—Na1i	87.67 (9)
O6iv—Na1—Na1iv	39.43 (3)	Na1xiii—O4—Na1i	87.67 (9)
O6—Na1—Na1iv	85.26 (3)	Li1xi—O5—Na1	118.83 (9)
O5—Na1—Na1iv	123.70 (3)	Na1vi—O6—Na1	101.51 (5)

Symmetry codes: (i) x+1/3, x−y+2/3, z+1/6; (ii) −y+4/3, −x+2/3, z+1/6; (iii) −x+y+1/3, y−1/3, z+1/6; (iv) −x+y, −x, z; (v) −y+2/3, −x+1/3, z−1/6; (vi) −y, x−y, z; (vii) −y+1, x−y, z; (viii) −x+y+1, −x+1, z; (ix) −x+y, −x+1, z; (x) −y+1, x−y+1, z; (xi) −y+2/3, −x+4/3, z−1/6; (xii) −x+y+1/3, y+2/3, z+1/6; (xiii) −y+1/3, −x+2/3, z+1/6.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Crystal data

3(Na)Li2(SO4)6(H2O)	Dx = 2.018 Mg m−3
Mr = 376.13	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c:H	Cell parameters from 4304 reflections
a = 8.426 (2) Å	θ = 2.6–21.0°
c = 30.197 (4) Å	µ = 0.61 mm−1
V = 1856.6 (10) Å3	T = 260 K
Z = 6	Needle, colourless
F(000) = 1152	0.3 × 0.15 × 0.1 mm

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Data collection

Stoe IPDS 2 diffractometer	915 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	906 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.034
Detector resolution: 6.67 pixels mm-1	θmax = 27.2°, θmin = 3.1°
rotation method scans	h = −10→10
Absorption correction: integration Coppens (1970)	k = −9→10
Tmin = 0.864, Tmax = 0.938	l = −38→38
5068 measured reflections

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Refinement

Refinement on F2	All H-atom parameters refined
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0254P)2 + 0.5038P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.017	(Δ/σ)max < 0.001
wR(F2) = 0.043	Δρmax = 0.14 e Å−3
S = 1.13	Δρmin = −0.20 e Å−3
915 reflections	Extinction correction: SHELXL2018/3 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
78 parameters	Extinction coefficient: 0.0031 (4)
1 restraint	Absolute structure: Flack x determined using 437 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Hydrogen site location: difference Fourier map	Absolute structure parameter: −0.04 (6)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Li1	0.333333	0.666667	0.8465 (2)	0.0164 (12)
Na1	0.76508 (11)	0.73321 (11)	0.93934 (4)	0.0204 (2)
S1	0.333333	0.666667	0.95693 (2)	0.01085 (19)
S2	0.666667	0.333333	0.87429 (2)	0.01117 (19)
O1	0.6085 (2)	0.46143 (19)	0.89076 (5)	0.0167 (3)
O2	0.4815 (2)	0.6374 (2)	0.97377 (5)	0.0188 (3)
O3	0.333333	0.666667	0.90900 (9)	0.0282 (7)
O4	0.666667	0.333333	0.82539 (8)	0.0181 (6)
O5	0.8541 (2)	0.56971 (19)	0.99018 (5)	0.0172 (3)
H5A	0.949 (5)	0.569 (4)	0.9803 (10)	0.027 (8)*
H5B	0.890 (4)	0.630 (4)	1.0103 (11)	0.027 (8)*
O6	1.0306 (2)	0.7917 (2)	0.89835 (6)	0.0200 (3)
H6B	1.014 (5)	0.690 (6)	0.8961 (11)	0.045 (10)*
H6A	1.017 (5)	0.807 (5)	0.8738 (12)	0.044 (10)*

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Li1	0.0178 (17)	0.0178 (17)	0.014 (3)	0.0089 (9)	0.000	0.000
Na1	0.0190 (4)	0.0218 (4)	0.0207 (4)	0.0104 (4)	0.0049 (3)	0.0054 (3)
S1	0.0115 (2)	0.0115 (2)	0.0096 (4)	0.00575 (12)	0.000	0.000
S2	0.0113 (2)	0.0113 (2)	0.0109 (4)	0.00565 (12)	0.000	0.000
O1	0.0181 (7)	0.0165 (7)	0.0194 (7)	0.0114 (6)	−0.0007 (5)	−0.0030 (5)
O2	0.0160 (7)	0.0236 (7)	0.0222 (7)	0.0138 (6)	0.0009 (6)	0.0032 (6)
O3	0.0384 (11)	0.0384 (11)	0.0076 (14)	0.0192 (6)	0.000	0.000
O4	0.0221 (9)	0.0221 (9)	0.0102 (12)	0.0110 (4)	0.000	0.000
O5	0.0184 (7)	0.0154 (7)	0.0171 (7)	0.0079 (6)	0.0020 (6)	−0.0013 (6)
O6	0.0223 (8)	0.0196 (8)	0.0179 (7)	0.0102 (7)	0.0005 (6)	−0.0009 (6)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-260K). Geometric parameters (Å, º)

Li1—O3	1.888 (6)	Na1—O4v	2.656 (2)
Li1—O5i	1.948 (3)	Na1—Na1iv	3.6830 (17)
Li1—O5ii	1.948 (3)	Na1—Na1vi	3.6830 (17)
Li1—O5iii	1.948 (3)	S1—O3	1.447 (3)
Li1—Na1iii	3.770 (4)	S1—O2	1.4788 (15)
Li1—Na1i	3.770 (4)	S1—O2vii	1.4788 (15)
Li1—Na1ii	3.770 (4)	S1—O2viii	1.4788 (15)
Na1—O2	2.3478 (17)	S2—O4	1.477 (2)
Na1—O6iv	2.3584 (18)	S2—O1ix	1.4769 (14)
Na1—O6	2.3825 (19)	S2—O1x	1.4769 (14)
Na1—O5	2.4188 (16)	S2—O1	1.4769 (14)
Na1—O1	2.4727 (17)
O3—Li1—O5i	110.85 (17)	O1—Na1—Na1iv	142.14 (4)
O3—Li1—O5ii	110.85 (17)	O4v—Na1—Na1iv	46.11 (4)
O5i—Li1—O5ii	108.06 (18)	O2—Na1—Na1vi	149.08 (5)
O3—Li1—O5iii	110.85 (17)	O6iv—Na1—Na1vi	85.36 (5)
O5i—Li1—O5iii	108.06 (18)	O6—Na1—Na1vi	38.79 (4)
O5ii—Li1—O5iii	108.06 (18)	O5—Na1—Na1vi	79.18 (5)
O3—Li1—Na1iii	126.24 (8)	O1—Na1—Na1vi	122.10 (5)
O5i—Li1—Na1iii	118.2 (2)	O4v—Na1—Na1vi	46.11 (4)
O5ii—Li1—Na1iii	73.96 (12)	Na1iv—Na1—Na1vi	60.000 (1)
O5iii—Li1—Na1iii	34.14 (9)	O2—Na1—Li1xi	72.52 (5)
O3—Li1—Na1i	126.24 (8)	O6iv—Na1—Li1xi	167.16 (6)
O5i—Li1—Na1i	34.14 (9)	O6—Na1—Li1xi	104.84 (6)
O5ii—Li1—Na1i	118.2 (2)	O5—Na1—Li1xi	26.88 (5)
O5iii—Li1—Na1i	73.96 (12)	O1—Na1—Li1xi	75.28 (8)
Na1iii—Li1—Na1i	88.61 (11)	O4v—Na1—Li1xi	98.04 (8)
O3—Li1—Na1ii	126.24 (8)	Na1iv—Na1—Li1xi	142.58 (7)
O5i—Li1—Na1ii	73.96 (12)	Na1vi—Na1—Li1xi	105.97 (3)
O5ii—Li1—Na1ii	34.14 (9)	O3—S1—O2	110.11 (7)
O5iii—Li1—Na1ii	118.2 (2)	O3—S1—O2vii	110.12 (7)
Na1iii—Li1—Na1ii	88.61 (11)	O2—S1—O2vii	108.82 (7)
Na1i—Li1—Na1ii	88.61 (11)	O3—S1—O2viii	110.12 (7)
O2—Na1—O6iv	94.66 (6)	O2—S1—O2viii	108.82 (7)
O2—Na1—O6	171.88 (7)	O2vii—S1—O2viii	108.82 (7)
O6iv—Na1—O6	87.76 (9)	O4—S2—O1ix	109.68 (7)
O2—Na1—O5	94.30 (6)	O4—S2—O1x	109.68 (7)
O6iv—Na1—O5	162.39 (7)	O1ix—S2—O1x	109.26 (7)
O6—Na1—O5	85.48 (7)	O4—S2—O1	109.69 (6)
O2—Na1—O1	87.96 (6)	O1ix—S2—O1	109.26 (7)
O6iv—Na1—O1	104.13 (6)	O1x—S2—O1	109.26 (7)
O6—Na1—O1	83.93 (6)	S2—O1—Na1	131.17 (9)
O5—Na1—O1	91.31 (6)	S1—O2—Na1	126.11 (9)
O2—Na1—O4v	103.01 (6)	S1—O3—Li1	180.0
O6iv—Na1—O4v	85.37 (6)	S2—O4—Na1xii	126.82 (5)
O6—Na1—O4v	84.90 (6)	S2—O4—Na1xiii	126.82 (5)
O5—Na1—O4v	77.85 (6)	Na1xii—O4—Na1xiii	87.78 (7)
O1—Na1—O4v	165.00 (5)	S2—O4—Na1iii	126.82 (5)
O2—Na1—Na1iv	101.74 (5)	Na1xii—O4—Na1iii	87.78 (7)
O6iv—Na1—Na1iv	39.26 (5)	Na1xiii—O4—Na1iii	87.78 (7)
O6—Na1—Na1iv	85.03 (4)	Li1xi—O5—Na1	118.98 (12)
O5—Na1—Na1iv	123.73 (5)	Na1vi—O6—Na1	101.95 (7)

Symmetry codes: (i) −x+y+2/3, y+1/3, z−1/6; (ii) −y+2/3, −x+4/3, z−1/6; (iii) x−1/3, x−y+1/3, z−1/6; (iv) −x+y+1, −x+2, z; (v) −y+4/3, −x+5/3, z+1/6; (vi) −y+2, x−y+1, z; (vii) −y+1, x−y+1, z; (viii) −x+y, −x+1, z; (ix) −x+y+1, −x+1, z; (x) −y+1, x−y, z; (xi) −y+4/3, −x+2/3, z+1/6; (xii) −x+y+2/3, y−2/3, z−1/6; (xiii) −y+5/3, −x+4/3, z−1/6.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Crystal data

3(Na)Li2(SO4)6(H2O)	Dx = 2.012 Mg m−3
Mr = 376.13	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c:H	Cell parameters from 10790 reflections
a = 8.4337 (17) Å	θ = 2.8–27.5°
c = 30.235 (6) Å	µ = 0.61 mm−1
V = 1862.4 (8) Å3	T = 273 K
Z = 6	Needle, colourless
F(000) = 1152	0.3 × 0.15 × 0.1 mm

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Data collection

Stoe IPDS 2 diffractometer	1159 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	1141 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.035
Detector resolution: 6.67 pixels mm-1	θmax = 29.6°, θmin = 3.1°
rotation method scans	h = −11→11
Absorption correction: integration Coppens (1970)	k = −10→11
Tmin = 0.773, Tmax = 0.866	l = −40→40
8584 measured reflections

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Refinement

Refinement on F2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F2 > 2σ(F2)] = 0.019	w = 1/[σ2(Fo2) + (0.0212P)2 + 1.6465P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.053	(Δ/σ)max < 0.001
S = 1.28	Δρmax = 0.19 e Å−3
1159 reflections	Δρmin = −0.33 e Å−3
77 parameters	Absolute structure: Flack x determined using 551 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
1 restraint	Absolute structure parameter: 0.04 (4)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Li1	0.666667	0.333333	0.1535 (2)	0.0180 (12)
Na1	0.23496 (12)	0.26693 (13)	0.06069 (4)	0.0207 (2)
S1	0.666667	0.333333	0.04304 (3)	0.01061 (16)
S2	0.333333	0.666667	0.12574 (3)	0.01110 (16)
O1	0.3914 (2)	0.5385 (2)	0.10929 (5)	0.0170 (3)
O2	0.5185 (2)	0.3624 (2)	0.02624 (6)	0.0193 (3)
O3	0.666667	0.333333	0.09098 (10)	0.0290 (7)
O4	0.333333	0.666667	0.17459 (9)	0.0190 (5)
O5	0.1459 (2)	0.4305 (2)	0.00968 (6)	0.0174 (3)
H5A	0.047 (6)	0.434 (5)	0.0201 (13)	0.034 (10)*
H5B	0.108 (5)	0.365 (5)	−0.0120 (13)	0.030 (9)*
O6	−0.0306 (2)	0.2082 (2)	0.10174 (6)	0.0205 (3)
H6B	−0.009 (6)	0.314 (7)	0.1031 (13)	0.043 (11)*
H6A	−0.023 (7)	0.188 (6)	0.1279 (15)	0.051 (12)*

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Li1	0.0190 (18)	0.0190 (18)	0.016 (3)	0.0095 (9)	0.000	0.000
Na1	0.0189 (4)	0.0228 (5)	0.0206 (4)	0.0107 (4)	0.0053 (3)	0.0055 (4)
S1	0.0116 (2)	0.0116 (2)	0.0087 (3)	0.00578 (11)	0.000	0.000
S2	0.0112 (2)	0.0112 (2)	0.0108 (4)	0.00562 (11)	0.000	0.000
O1	0.0181 (7)	0.0173 (7)	0.0192 (7)	0.0117 (6)	−0.0011 (6)	−0.0032 (6)
O2	0.0166 (7)	0.0242 (8)	0.0224 (7)	0.0141 (6)	0.0000 (6)	0.0033 (6)
O3	0.0393 (12)	0.0393 (12)	0.0083 (13)	0.0196 (6)	0.000	0.000
O4	0.0230 (8)	0.0230 (8)	0.0110 (12)	0.0115 (4)	0.000	0.000
O5	0.0186 (7)	0.0158 (7)	0.0173 (7)	0.0083 (6)	0.0021 (6)	−0.0009 (6)
O6	0.0235 (9)	0.0193 (8)	0.0186 (8)	0.0106 (7)	0.0004 (6)	−0.0009 (7)

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Geometric parameters (Å, º)

Li1—O3	1.889 (7)	Na1—O4v	2.661 (2)
Li1—O5i	1.948 (3)	Na1—Na1vi	3.6879 (18)
Li1—O5ii	1.948 (3)	Na1—Na1iv	3.6879 (18)
Li1—O5iii	1.948 (3)	S1—O3	1.449 (3)
Li1—Na1i	3.775 (4)	S1—O2vii	1.4783 (16)
Li1—Na1iii	3.775 (4)	S1—O2	1.4783 (16)
Li1—Na1ii	3.775 (4)	S1—O2viii	1.4783 (16)
Na1—O2	2.3509 (19)	S2—O4	1.477 (3)
Na1—O6iv	2.362 (2)	S2—O1ix	1.4781 (16)
Na1—O6	2.386 (2)	S2—O1x	1.4781 (16)
Na1—O5	2.4253 (18)	S2—O1	1.4781 (16)
Na1—O1	2.4745 (18)
O3—Li1—O5i	110.80 (19)	O1—Na1—Na1vi	122.09 (5)
O3—Li1—O5ii	110.80 (19)	O4v—Na1—Na1vi	46.13 (4)
O5i—Li1—O5ii	108.1 (2)	O2—Na1—Na1iv	101.65 (6)
O3—Li1—O5iii	110.80 (19)	O6iv—Na1—Na1iv	39.26 (5)
O5i—Li1—O5iii	108.1 (2)	O6—Na1—Na1iv	84.99 (5)
O5ii—Li1—O5iii	108.1 (2)	O5—Na1—Na1iv	123.70 (5)
O3—Li1—Na1i	126.29 (8)	O1—Na1—Na1iv	142.09 (4)
O5i—Li1—Na1i	34.22 (10)	O4v—Na1—Na1iv	46.13 (4)
O5ii—Li1—Na1i	73.93 (13)	Na1vi—Na1—Na1iv	60.0
O5iii—Li1—Na1i	118.2 (3)	O2—Na1—Li1xi	72.56 (5)
O3—Li1—Na1iii	126.29 (8)	O6iv—Na1—Li1xi	167.19 (6)
O5i—Li1—Na1iii	73.93 (13)	O6—Na1—Li1xi	104.94 (7)
O5ii—Li1—Na1iii	118.2 (3)	O5—Na1—Li1xi	26.85 (5)
O5iii—Li1—Na1iii	34.22 (10)	O1—Na1—Li1xi	75.37 (9)
Na1i—Li1—Na1iii	88.54 (12)	O4v—Na1—Li1xi	97.99 (9)
O3—Li1—Na1ii	126.29 (8)	Na1vi—Na1—Li1xi	105.97 (4)
O5i—Li1—Na1ii	118.2 (3)	Na1iv—Na1—Li1xi	142.53 (8)
O5ii—Li1—Na1ii	34.22 (10)	O3—S1—O2vii	110.10 (8)
O5iii—Li1—Na1ii	73.93 (13)	O3—S1—O2	110.10 (8)
Na1i—Li1—Na1ii	88.54 (12)	O2vii—S1—O2	108.83 (8)
Na1iii—Li1—Na1ii	88.54 (12)	O3—S1—O2viii	110.10 (8)
O2—Na1—O6iv	94.65 (7)	O2vii—S1—O2viii	108.83 (8)
O2—Na1—O6	171.96 (7)	O2—S1—O2viii	108.83 (8)
O6iv—Na1—O6	87.63 (9)	O4—S2—O1ix	109.66 (7)
O2—Na1—O5	94.28 (6)	O4—S2—O1x	109.66 (7)
O6iv—Na1—O5	162.35 (7)	O1ix—S2—O1x	109.28 (7)
O6—Na1—O5	85.62 (7)	O4—S2—O1	109.66 (7)
O2—Na1—O1	88.05 (7)	O1ix—S2—O1	109.28 (7)
O6iv—Na1—O1	104.07 (6)	O1x—S2—O1	109.28 (7)
O6—Na1—O1	83.92 (6)	S2—O1—Na1	131.18 (9)
O5—Na1—O1	91.41 (6)	S1—O2—Na1	126.18 (10)
O2—Na1—O4v	102.93 (7)	S1—O3—Li1	180.0
O6iv—Na1—O4v	85.39 (6)	S2—O4—Na1xii	126.84 (6)
O6—Na1—O4v	84.92 (6)	S2—O4—Na1xiii	126.84 (6)
O5—Na1—O4v	77.80 (6)	Na1xii—O4—Na1xiii	87.75 (8)
O1—Na1—O4v	165.02 (5)	S2—O4—Na1i	126.84 (6)
O2—Na1—Na1vi	149.02 (5)	Na1xii—O4—Na1i	87.75 (8)
O6iv—Na1—Na1vi	85.31 (5)	Na1xiii—O4—Na1i	87.75 (8)
O6—Na1—Na1vi	38.80 (5)	Li1xi—O5—Na1	118.93 (13)
O5—Na1—Na1vi	79.22 (5)	Na1vi—O6—Na1	101.94 (8)

Symmetry codes: (i) x+1/3, x−y+2/3, z+1/6; (ii) −y+4/3, −x+2/3, z+1/6; (iii) −x+y+1/3, y−1/3, z+1/6; (iv) −x+y, −x, z; (v) −y+2/3, −x+1/3, z−1/6; (vi) −y, x−y, z; (vii) −y+1, x−y, z; (viii) −x+y+1, −x+1, z; (ix) −x+y, −x+1, z; (x) −y+1, x−y+1, z; (xi) −y+2/3, −x+4/3, z−1/6; (xii) −x+y+1/3, y+2/3, z+1/6; (xiii) −y+1/3, −x+2/3, z+1/6.

Sodium-Lithium-Sulfate-Hexahydrate (Na3_Li_2SO4_6H2O-273K). Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H6A···O2xiii	0.77 (5)	2.00 (5)	2.764 (11)	170 (5)
O6—H6B···O1	0.83 (4)	2.15 (4)	2.937 (7)	157 (4)
O5—H5B···O1xiv	0.79 (4)	1.92 (4)	2.694 (7)	165 (4)
O5—H5A···O2ix	0.89 (4)	1.97 (4)	2.828 (6)	163 (3)

Symmetry codes: (ix) −x+y, −x+1, z; (xiii) −y+1/3, −x+2/3, z+1/6; (xiv) x−1/3, x−y+1/3, z−1/6.

(Na3_Li_2SO4_6H2O-293K). Crystal data

H12LiNa3O14S2	Dx = 1.995 Mg m−3
Mr = 376.13	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c:H	Cell parameters from 5111 reflections
a = 8.457 (7) Å	θ = 2.9–27.1°
c = 30.33 (3) Å	µ = 0.60 mm−1
V = 1879 (4) Å3	T = 293 K
Z = 6	Needle, colourless
F(000) = 1152	0.3 × 0.15 × 0.1 mm

(Na3_Li_2SO4_6H2O-293K). Data collection

Stoe IPDS 2T diffractometer	730 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	695 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.054
Detector resolution: 6.67 pixels mm-1	θmax = 27.1°, θmin = 3.9°
rotation method scans	h = −9→10
Absorption correction: integration Coppens (1970)	k = −6→10
Tmin = 0.517, Tmax = 0.844	l = −38→35
1376 measured reflections

(Na3_Li_2SO4_6H2O-293K). Refinement

Refinement on F2	All H-atom parameters refined
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0771P)2 + 1.3675P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.038	(Δ/σ)max < 0.001
wR(F2) = 0.105	Δρmax = 0.33 e Å−3
S = 1.11	Δρmin = −0.47 e Å−3
730 reflections	Extinction correction: SHELXL2018/3 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
78 parameters	Extinction coefficient: 0.0054 (14)
5 restraints	Absolute structure: Classical Flack method preferred over Parsons because s.u. lower
Hydrogen site location: difference Fourier map	Absolute structure parameter: −0.3 (3)

(Na3_Li_2SO4_6H2O-293K). Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

(Na3_Li_2SO4_6H2O-293K). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Li1	0.666667	0.333333	0.1539 (4)	0.026 (3)
Na1	0.2353 (3)	0.2672 (3)	0.06061 (9)	0.0300 (5)
S1	0.666667	0.333333	0.04301 (5)	0.0167 (4)
S2	0.333333	0.666667	0.12572 (5)	0.0169 (4)
O1	0.3912 (5)	0.5387 (4)	0.10917 (11)	0.0263 (7)
O2	0.5187 (4)	0.3622 (5)	0.02643 (11)	0.0291 (7)
O3	0.666667	0.333333	0.0906 (2)	0.0365 (18)
O4	0.333333	0.666667	0.1745 (2)	0.0250 (13)
O5	0.1454 (5)	0.4298 (4)	0.00960 (11)	0.0256 (7)
H5A	0.059 (6)	0.440 (9)	0.018 (2)	0.035 (17)*
H5B	0.096 (9)	0.354 (8)	−0.0099 (18)	0.039 (16)*
O6	−0.0302 (5)	0.2083 (4)	0.10168 (12)	0.0290 (7)
H6B	−0.001 (11)	0.317 (3)	0.101 (3)	0.05 (2)*
H6A	−0.030 (11)	0.173 (10)	0.1268 (10)	0.042 (18)*

(Na3_Li_2SO4_6H2O-293K). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Li1	0.027 (4)	0.027 (4)	0.025 (7)	0.014 (2)	0.000	0.000
Na1	0.0298 (9)	0.0331 (10)	0.0285 (9)	0.0167 (8)	0.0058 (7)	0.0065 (7)
S1	0.0188 (6)	0.0188 (6)	0.0127 (8)	0.0094 (3)	0.000	0.000
S2	0.0173 (6)	0.0173 (6)	0.0161 (9)	0.0087 (3)	0.000	0.000
O1	0.0312 (17)	0.0265 (16)	0.0266 (16)	0.0185 (14)	−0.0024 (12)	−0.0045 (12)
O2	0.0261 (17)	0.0360 (17)	0.0297 (15)	0.0189 (14)	0.0011 (12)	0.0040 (13)
O3	0.048 (3)	0.048 (3)	0.013 (3)	0.0242 (15)	0.000	0.000
O4	0.029 (2)	0.029 (2)	0.017 (3)	0.0146 (11)	0.000	0.000
O5	0.0265 (16)	0.0226 (15)	0.0271 (14)	0.0118 (13)	0.0003 (11)	−0.0005 (10)
O6	0.0351 (19)	0.0276 (18)	0.0243 (15)	0.0156 (16)	0.0013 (12)	0.0008 (13)

(Na3_Li_2SO4_6H2O-293K). Geometric parameters (Å, º)

Li1—O3	1.920 (15)	Na1—O4v	2.671 (5)
Li1—O5i	1.953 (6)	Na1—Na1iv	3.702 (5)
Li1—O5ii	1.953 (6)	Na1—Na1vi	3.702 (5)
Li1—O5iii	1.953 (6)	S1—O3	1.443 (6)
Li1—Na1ii	3.775 (8)	S1—O2	1.477 (3)
Li1—Na1iii	3.775 (8)	S1—O2vii	1.477 (3)
Li1—Na1i	3.775 (8)	S1—O2viii	1.477 (3)
Na1—O2	2.354 (4)	S2—O4	1.479 (6)
Na1—O6iv	2.372 (4)	S2—O1ix	1.480 (3)
Na1—O6	2.392 (4)	S2—O1x	1.480 (3)
Na1—O5	2.431 (4)	S2—O1	1.480 (3)
Na1—O1	2.481 (4)
O3—Li1—O5i	110.3 (4)	O1—Na1—Na1iv	142.12 (9)
O3—Li1—O5ii	110.3 (4)	O4v—Na1—Na1iv	46.12 (9)
O5i—Li1—O5ii	108.6 (4)	O2—Na1—Na1vi	149.12 (10)
O3—Li1—O5iii	110.3 (4)	O6iv—Na1—Na1vi	85.24 (9)
O5i—Li1—O5iii	108.6 (4)	O6—Na1—Na1vi	38.80 (10)
O5ii—Li1—O5iii	108.6 (4)	O5—Na1—Na1vi	79.04 (11)
O3—Li1—Na1ii	126.13 (16)	O1—Na1—Na1vi	122.00 (10)
O5i—Li1—Na1ii	118.8 (5)	O4v—Na1—Na1vi	46.12 (9)
O5ii—Li1—Na1ii	34.45 (19)	Na1iv—Na1—Na1vi	60.0
O5iii—Li1—Na1ii	74.2 (2)	O2—Na1—Li1xi	72.81 (11)
O3—Li1—Na1iii	126.13 (16)	O6iv—Na1—Li1xi	167.34 (12)
O5i—Li1—Na1iii	74.2 (2)	O6—Na1—Li1xi	104.87 (13)
O5ii—Li1—Na1iii	118.8 (5)	O5—Na1—Li1xi	27.04 (10)
O5iii—Li1—Na1iii	34.45 (19)	O1—Na1—Li1xi	75.20 (18)
Na1ii—Li1—Na1iii	88.8 (2)	O4v—Na1—Li1xi	98.10 (19)
O3—Li1—Na1i	126.13 (16)	Na1iv—Na1—Li1xi	142.67 (16)
O5i—Li1—Na1i	34.45 (19)	Na1vi—Na1—Li1xi	105.96 (7)
O5ii—Li1—Na1i	74.2 (2)	O3—S1—O2	109.90 (16)
O5iii—Li1—Na1i	118.8 (5)	O3—S1—O2vii	109.90 (16)
Na1ii—Li1—Na1i	88.8 (2)	O2—S1—O2vii	109.04 (16)
Na1iii—Li1—Na1i	88.8 (2)	O3—S1—O2viii	109.90 (16)
O2—Na1—O6iv	94.56 (13)	O2—S1—O2viii	109.04 (16)
O2—Na1—O6	171.91 (15)	O2vii—S1—O2viii	109.04 (16)
O6iv—Na1—O6	87.53 (17)	O4—S2—O1ix	109.82 (15)
O2—Na1—O5	94.58 (13)	O4—S2—O1x	109.82 (15)
O6iv—Na1—O5	162.10 (14)	O1ix—S2—O1x	109.13 (15)
O6—Na1—O5	85.57 (14)	O4—S2—O1	109.82 (15)
O2—Na1—O1	88.07 (14)	O1ix—S2—O1	109.12 (15)
O6iv—Na1—O1	104.17 (14)	O1x—S2—O1	109.12 (15)
O6—Na1—O1	83.84 (12)	S2—O1—Na1	131.4 (2)
O5—Na1—O1	91.50 (13)	S1—O2—Na1	126.6 (2)
O2—Na1—O4v	103.02 (15)	S1—O3—Li1	180.0
O6iv—Na1—O4v	85.33 (14)	S2—O4—Na1xii	126.84 (13)
O6—Na1—O4v	84.92 (14)	S2—O4—Na1xiii	126.84 (13)
O5—Na1—O4v	77.62 (14)	Na1xii—O4—Na1xiii	87.75 (19)
O1—Na1—O4v	164.92 (11)	S2—O4—Na1i	126.84 (13)
O2—Na1—Na1iv	101.59 (12)	Na1xii—O4—Na1i	87.75 (19)
O6iv—Na1—Na1iv	39.20 (10)	Na1xiii—O4—Na1i	87.75 (19)
O6—Na1—Na1iv	84.96 (9)	Li1xi—O5—Na1	118.5 (3)
O5—Na1—Na1iv	123.52 (10)	Na1vi—O6—Na1	102.00 (15)

Symmetry codes: (i) x+1/3, x−y+2/3, z+1/6; (ii) −y+4/3, −x+2/3, z+1/6; (iii) −x+y+1/3, y−1/3, z+1/6; (iv) −x+y, −x, z; (v) −y+2/3, −x+1/3, z−1/6; (vi) −y, x−y, z; (vii) −y+1, x−y, z; (viii) −x+y+1, −x+1, z; (ix) −x+y, −x+1, z; (x) −y+1, x−y+1, z; (xi) −y+2/3, −x+4/3, z−1/6; (xii) −x+y+1/3, y+2/3, z+1/6; (xiii) −y+1/3, −x+2/3, z+1/6.