Strontium disodium hexa­thio­diphosphate(IV) octa­hydrate

Abstract

The crystal structure of SrNa₂(P₂S₆)·8H₂O is isotypic with that of its calcium analogue. The asymmetric unit consists of one Sr²⁺ cation (2 symmetry), two Na⁺ cations (2 and symmetry, respectively), one-half of a centrosymmetric (P₂S₆)⁴⁻ anion with a staggered confirmation and four water mol­ecules. The crystal structure is built up from layers of cations and anions extending parallel to (101). Each SrO₈ polyhedron is connected via edge-sharing to two NaO₄S₂ octa­hedra and to one NaO₂S₄ octa­hedron. The NaO₄S₂ octa­edra are, in turn, connected with two (P₂S₆)⁴⁻ anions through common corners. Adjacent layers are held together by several O—H⋯S hydrogen-bonding inter­actions.

Related literature

For background to thio­diphosphates(IV), including their crystal structures, see: Jörgens et al. (2003 ▶); Klingen et al. (1973 ▶). For the synthesis of Na₄(P₂S₆)·6H₂O, see: Fincher et al. (1998 ▶). For the isotypic structure of CaNa₂(P₂S₆)·8H₂O, see: Ehrhardt &Gjikaj (2010 ▶).

Experimental

Crystal data

• SrNa₂(P₂S₆)·8H₂O

• M _r = 532.03

• Monoclinic,

• a = 14.9010 (19) Å

• b = 9.3282 (7) Å

• c = 14.1338 (19) Å

• β = 114.918 (10)°

• V = 1781.7 (4) ų

• Z = 4

• Mo Kα radiation

• μ = 3.98 mm⁻¹

• T = 223 K

• 0.28 × 0.26 × 0.25 mm

Data collection

• Stoe IPDS 2 diffractometer

• 14472 measured reflections

• 2544 independent reflections

• 2302 reflections with I > 2σ(I)

• R _int = 0.064

Refinement

• R[F ² > 2σ(F ²)] = 0.036

• wR(F ²) = 0.087

• S = 1.12

• 2544 reflections

• 121 parameters

• All H-atom parameters refined

• Δρ_max = 1.14 e Å⁻³

• Δρ_min = −0.89 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2008 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2004 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Sr—O1	2.573 (2)
Sr—O2	2.596 (2)
Sr—O3	2.631 (2)
Sr—O4	2.6459 (19)
Na1—O3	2.345 (2)
Na1—O4	2.372 (2)
Na1—S2i	2.9741 (7)
Na2—O2	2.570 (3)
Na2—S1i	2.9525 (15)
Na2—S3	2.9924 (9)
P—S1	2.0162 (9)
P—S2	2.0243 (9)
P—S3	2.0248 (9)
P—Pi	2.2405 (12)

Symmetry code: (i) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯S3ii	0.76 (7)	2.66 (6)	3.324 (3)	146 (6)
O1—H1B⋯S2iii	0.86 (6)	2.53 (6)	3.306 (3)	151 (5)
O2—H2A⋯S2ii	0.82 (6)	2.51 (6)	3.334 (2)	176 (6)
O2—H2B⋯S2i	0.79 (5)	2.43 (5)	3.214 (2)	176 (5)
O3—H3A⋯S1iv	0.76 (7)	2.44 (7)	3.169 (2)	163 (5)
O3—H3B⋯S1ii	0.88 (7)	2.40 (7)	3.222 (2)	157 (6)
O4—H4A⋯S3v	0.95 (5)	2.29 (5)	3.245 (2)	175 (4)
O4—H4B⋯S3	0.91 (6)	2.30 (6)	3.199 (2)	171 (5)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

supplementary crystallographic information

Comment

Alkaline earth hypothiodiphosphates were first reported by Klingen et al. (1973). The structure of the title compound, SrNa₂(P₂S₆).8H₂O, is isotypic with that of its calcium analogue, CaNa₂(P₂S₆).8H₂O (Ehrhardt & Gjikaj, 2010). The asymmetric unit of SrNa₂(P₂S₆).8H₂O contains one Sr²⁺ cation, two Na⁺ cations, one half of a (P₂S₆)^4- anion and four water molecules (Fig. 1)

Na(1) is octahedrally coordinated by four H₂O molecules and two sulfur atoms of two (P₂S₆)^4- anions (Fig. 2). Na(2) is also octahedrally coordinated by two H₂O molecules and four sulfur atoms of two (P₂S₆)^4- anions (Fig. 3). The strontium cation is eightfold coordinated by water O atoms with Sr—O distances from 2.573 (2) to 2.6459 (19) Å. The SrO₈ coordination polyhedron can be described as a bicapped trigonal prism.

The crystal structure is built up from layers of cations and anions extending parallel to (101). Within the layer each SrO₈ polyhedron is connected by edge-sharing to two Na(1)O₄S₂ octahedra and to one Na(2)O₂S₄ octaedron. Furthermore, the Na(1)O₄S₂ octaedra are connected through common corners with two (P₂S₆)^4- anions.

The discrete ethane-like (P₂S₆)^4- anion has a staggered conformation and is located on a centre of inversion associated with the midpoint of the P—P bond. The corresponding P—P distance is 2.2405 (12) Å; the P—S distances range from 2.0162 (9) to 2.0248 (9) Å. These values agree well with those reported previously for other hypothiodiphosphate structures (Jörgens et al., 2003).

Neighbouring layers are held together by various O—H···S hydrogen bonding interactions. The donor—acceptor distances between O atoms of water molecules and S atoms of (P₂S₆)^4- units range from 3.169 to 3.334 Å (Table 2).

With the exception of the M-O bond lengths (M = Ca, Sr), all other bond lengths and angles as well as the O—H···S hydrogen bonding scheme are very similar in the two isotypic MNa₂(P₂S₆).8H₂O structures.

Experimental

Na₄(P₂S₆).6H₂O has been prepared according to Fincher et al. (1998). The title compound was obtained by adding a molar equivalent of strontium hydroxide to a solution of Na₄(P₂S₆).6H₂O in 70 ml distilled water at 348 K. Slow cooling to room temperature yielded colorless crystals of the title compound within some days.

Refinement

Hydrogen atoms were found from the difference Fourier map and were refined independently from their respective oxygen atoms with individual isotropic displacement parameters.

Figures

Fig. 1.

The crystal structure of CaNa2(P2S6).8H2O in a projection along [010].

Fig. 2.

Coordination of Na1 with the atom labelling scheme. The displacement ellipsoids are drawn at the 50% probability level. Symmetry codes as in Table 1. H atoms are represented as spheres of arbirtary radius.

Fig. 3.

View of the edge-shared CaO8 and Na(2)O2S4 polyhedra with the atom labelling scheme. The displacement ellipsoids are drawn at the 50% probability level. Symmetry codes as in Table 1. H atoms are represented as spheres of arbirtary radius.

Crystal data

SrNa2(P2S6)·8H2O	F(000) = 1064
Mr = 532.03	Dx = 1.983 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 14971 reflections
a = 14.9010 (19) Å	θ = 1.0–29.8°
b = 9.3282 (7) Å	µ = 3.98 mm−1
c = 14.1338 (19) Å	T = 223 K
β = 114.918 (10)°	Block, colorless
V = 1781.7 (4) Å3	0.28 × 0.26 × 0.25 mm
Z = 4

Data collection

Stoe IPDS 2 diffractometer	2302 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.064
graphite	θmax = 29.8°, θmin = 2.7°
ω–scans	h = −20→20
14472 measured reflections	k = −13→11
2544 independent reflections	l = −19→17

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.087	All H-atom parameters refined
S = 1.12	w = 1/[σ2(Fo2) + (0.0378P)2 + 5.0597P] where P = (Fo2 + 2Fc2)/3
2544 reflections	(Δ/σ)max < 0.001
121 parameters	Δρmax = 1.14 e Å−3
0 restraints	Δρmin = −0.88 e Å−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sr	0.5000	0.24637 (4)	0.2500	0.01746 (10)
Na1	0.2500	0.2500	0.0000	0.0260 (3)
Na2	0.5000	0.6875 (3)	0.2500	0.0440 (5)
P	0.20406 (5)	0.76351 (7)	0.04496 (5)	0.01570 (13)
S1	0.07286 (5)	0.67170 (8)	−0.04401 (6)	0.02445 (15)
S2	0.18992 (5)	0.97603 (7)	0.06433 (5)	0.01959 (14)
S3	0.28146 (5)	0.66742 (8)	0.18434 (5)	0.02452 (15)
O1	0.59794 (17)	0.0300 (3)	0.2305 (2)	0.0318 (5)
O2	0.50855 (17)	0.4687 (2)	0.14363 (17)	0.0259 (4)
O3	0.41245 (15)	0.1665 (2)	0.05340 (16)	0.0238 (4)
O4	0.31300 (14)	0.3293 (2)	0.17560 (15)	0.0220 (4)
H1A	0.627 (5)	0.042 (7)	0.197 (5)	0.08 (2)*
H1B	0.638 (4)	0.000 (6)	0.292 (5)	0.065 (17)*
H2A	0.555 (5)	0.473 (6)	0.127 (5)	0.070 (17)*
H2B	0.461 (4)	0.486 (5)	0.093 (4)	0.046 (13)*
H3A	0.404 (4)	0.086 (7)	0.048 (5)	0.067 (17)*
H3B	0.450 (5)	0.195 (8)	0.023 (5)	0.09 (2)*
H4A	0.282 (3)	0.283 (5)	0.214 (4)	0.037 (11)*
H4B	0.302 (4)	0.425 (7)	0.170 (4)	0.059 (15)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Sr	0.01698 (15)	0.01714 (16)	0.01694 (15)	0.000	0.00585 (11)	0.000
Na1	0.0230 (7)	0.0303 (9)	0.0221 (7)	0.0003 (6)	0.0068 (6)	−0.0014 (6)
Na2	0.0384 (10)	0.0598 (15)	0.0284 (9)	0.000	0.0086 (8)	0.000
P	0.0192 (3)	0.0137 (3)	0.0171 (3)	−0.0002 (2)	0.0104 (2)	−0.0003 (2)
S1	0.0209 (3)	0.0200 (3)	0.0336 (3)	−0.0042 (2)	0.0127 (3)	−0.0043 (3)
S2	0.0232 (3)	0.0145 (3)	0.0219 (3)	0.0012 (2)	0.0103 (2)	−0.0008 (2)
S3	0.0343 (3)	0.0226 (3)	0.0197 (3)	0.0094 (3)	0.0144 (3)	0.0058 (2)
O1	0.0232 (10)	0.0306 (12)	0.0366 (12)	0.0049 (8)	0.0076 (9)	−0.0042 (10)
O2	0.0237 (9)	0.0299 (11)	0.0224 (9)	0.0016 (8)	0.0081 (8)	0.0062 (8)
O3	0.0277 (10)	0.0218 (10)	0.0236 (9)	−0.0005 (8)	0.0126 (8)	−0.0037 (8)
O4	0.0242 (9)	0.0205 (9)	0.0229 (9)	0.0013 (7)	0.0115 (7)	0.0007 (8)

Geometric parameters (Å, °)

Sr—O1	2.573 (2)	Na1—S2iv	2.9741 (7)
Sr—O1i	2.573 (2)	Na2—O2	2.570 (3)
Sr—O2i	2.596 (2)	Na2—O2i	2.570 (3)
Sr—O2	2.596 (2)	Na2—S1iv	2.9525 (15)
Sr—O3	2.631 (2)	Na2—S1v	2.9525 (15)
Sr—O3i	2.631 (2)	Na2—S3	2.9924 (9)
Sr—O4	2.6459 (19)	Na2—S3i	2.9925 (9)
Sr—O4i	2.6459 (19)	P—S1	2.0162 (9)
Na1—O3ii	2.344 (2)	P—S2	2.0243 (9)
Na1—O3	2.345 (2)	P—S3	2.0248 (9)
Na1—O4	2.372 (2)	P—Piv	2.2405 (12)
Na1—O4ii	2.372 (2)	S1—Na2iv	2.9525 (15)
Na1—S2iii	2.9741 (7)	S2—Na1vi	2.9741 (7)
O1—Sr—O1i	76.65 (12)	O3—Na1—S2iii	91.09 (6)
O1—Sr—O2i	149.01 (7)	O4—Na1—S2iii	89.18 (5)
O1i—Sr—O2i	113.34 (9)	O4ii—Na1—S2iii	90.82 (5)
O1—Sr—O2	113.34 (9)	O3ii—Na1—S2iv	91.09 (6)
O1i—Sr—O2	149.01 (7)	O3—Na1—S2iv	88.91 (6)
O2i—Sr—O2	73.96 (10)	O4—Na1—S2iv	90.82 (5)
O1—Sr—O3	73.49 (8)	O4ii—Na1—S2iv	89.18 (5)
O1i—Sr—O3	80.77 (8)	S2iii—Na1—S2iv	180.0
O2i—Sr—O3	135.60 (7)	O2—Na2—O2i	74.82 (12)
O2—Sr—O3	74.82 (7)	O2—Na2—S1iv	82.23 (5)
O1—Sr—O3i	80.78 (8)	O2i—Na2—S1iv	147.35 (8)
O1i—Sr—O3i	73.50 (8)	O2—Na2—S1v	147.35 (8)
O2i—Sr—O3i	74.82 (7)	O2i—Na2—S1v	82.23 (5)
O2—Sr—O3i	135.59 (7)	S1iv—Na2—S1v	127.17 (10)
O3—Sr—O3i	147.09 (10)	O2—Na2—S3	94.85 (7)
O1—Sr—O4	137.47 (7)	O2i—Na2—S3	79.40 (6)
O1i—Sr—O4	73.86 (7)	S1iv—Na2—S3	79.75 (3)
O2i—Sr—O4	72.30 (7)	S1v—Na2—S3	103.51 (3)
O2—Sr—O4	80.60 (7)	O2—Na2—S3i	79.40 (6)
O3—Sr—O4	72.10 (6)	O2i—Na2—S3i	94.85 (7)
O3i—Sr—O4	118.24 (6)	S1iv—Na2—S3i	103.51 (3)
O1—Sr—O4i	73.86 (7)	S1v—Na2—S3i	79.75 (3)
O1i—Sr—O4i	137.47 (7)	S3—Na2—S3i	172.83 (11)
O2i—Sr—O4i	80.60 (7)	S1—P—S2	111.81 (4)
O2—Sr—O4i	72.30 (7)	S1—P—S3	115.08 (4)
O3—Sr—O4i	118.23 (6)	S2—P—S3	110.55 (4)
O3i—Sr—O4i	72.10 (6)	S1—P—Piv	105.20 (5)
O4—Sr—O4i	145.98 (9)	S2—P—Piv	108.07 (5)
O3ii—Na1—O3	180.0	S3—P—Piv	105.57 (5)
O3ii—Na1—O4	97.64 (7)	P—S1—Na2iv	106.45 (5)
O3—Na1—O4	82.36 (7)	P—S2—Na1vi	137.58 (3)
O3ii—Na1—O4ii	82.36 (7)	P—S3—Na2	111.92 (4)
O3—Na1—O4ii	97.64 (7)	Na2—O2—Sr	105.61 (9)
O4—Na1—O4ii	180.0	Na1—O3—Sr	103.36 (8)
O3ii—Na1—S2iii	88.91 (6)	Na1—O4—Sr	102.17 (7)

Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+1/2, −y+1/2, −z; (iii) x, y−1, z; (iv) −x+1/2, −y+3/2, −z; (v) x+1/2, −y+3/2, z+1/2; (vi) x, y+1, z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···S3vii	0.76 (7)	2.66 (6)	3.324 (3)	146 (6)
O1—H1B···S2viii	0.86 (6)	2.53 (6)	3.306 (3)	151 (5)
O2—H2A···S2vii	0.82 (6)	2.51 (6)	3.334 (2)	176 (6)
O2—H2B···S2iv	0.79 (5)	2.43 (5)	3.214 (2)	176 (5)
O3—H3A···S1ii	0.76 (7)	2.44 (7)	3.169 (2)	163 (5)
O3—H3B···S1vii	0.88 (7)	2.40 (7)	3.222 (2)	157 (6)
O4—H4A···S3ix	0.95 (5)	2.29 (5)	3.245 (2)	175 (4)
O4—H4B···S3	0.91 (6)	2.30 (6)	3.199 (2)	171 (5)

Symmetry codes: (vii) x+1/2, y−1/2, z; (viii) −x+1, y−1, −z+1/2; (iv) −x+1/2, −y+3/2, −z; (ii) −x+1/2, −y+1/2, −z; (ix) −x+1/2, y−1/2, −z+1/2.