Lithium diaqua­nickel(II) catena-borodiphosphate(V) monohydrate

Abstract

The title borophosphate LiNi(H₂O)₂[BP₂O₈]·H₂O was synthesized under hydro­thermal conditions. The crystal structure is isotypic with the Mg analogue and features helical [BP₂O₈]³⁻ borophosphate ribbons, constructed by BO₄ (2 symmetry) and PO₄ tetra­hedra. The borate groups share all their oxygen apices with adjacent phosphate tetra­hedra. The ribbons are connected via Ni²⁺ cations that are located on twofold rotation axes. The cations have a slightly distorted octa­hedral oxygen coordination by four O atoms from the anion and by two water mol­ecules. The voids within the helices are occupied by Li⁺ cations, likewise located on twofold rotation axes, in an irregular environment of five O atoms. The structure is stabilized by O—H⋯O hydrogen bonds between coordinated or uncoordinated water mol­ecules and O atoms that are part of the helices.

Related literature

For the isotypic Mg analogue, see: Lin et al. (2008 ▶). For other borophosphates, see: Boy & Kniep (2001 ▶); Kniep et al. (1998 ▶). A review on the structural chemistry of borophosphates is given by Ewald et al. (2007 ▶).

Experimental

Crystal data

• LiNi(H₂O)₂[BP₂O₈]·H₂O

• M _r = 320.44

• Hexagonal,

• a = 9.3359 (3) Å

• c = 15.7497 (11) Å

• V = 1188.82 (10) ų

• Z = 6

• Mo Kα radiation

• μ = 2.91 mm⁻¹

• T = 296 K

• 0.22 × 0.20 × 0.17 mm

Data collection

• Bruker APEXII CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.567, T _max = 0.638

• 6139 measured reflections

• 708 independent reflections

• 684 reflections with I > 2σ(I)

• R _int = 0.049

Refinement

• R[F ² > 2σ(F ²)] = 0.026

• wR(F ²) = 0.065

• S = 1.14

• 708 reflections

• 75 parameters

• H-atom parameters constrained

• Δρ_max = 0.68 e Å⁻³

• Δρ_min = −0.39 e Å⁻³

• Absolute structure: Flack (1983 ▶), 235 Friedel pairs

• Flack parameter: 0.01 (3)

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Selected bond lengths (Å).

Ni1—O1i	2.048 (3)
Ni1—O2	2.070 (3)
Ni1—O3	2.130 (3)
P2—O1	1.503 (3)
P2—O2	1.510 (3)
P2—O4	1.546 (3)
P2—O5	1.556 (3)
O6—Li	2.12 (2)
B—O5ii	1.461 (5)
B—O4iii	1.471 (5)
Li—O2iv	2.113 (13)
Li—O3v	2.164 (4)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯O5iv	0.81	2.01	2.746 (4)	151
O3—H3A⋯O2iv	0.81	2.60	3.165 (4)	128
O6—H6⋯O4vi	0.83	2.52	3.331 (4)	167
O6—H6⋯O1vi	0.83	2.66	3.092 (4)	114
O3—H3B⋯O1	0.83	2.00	2.810 (4)	167
O3—H3B⋯O2	0.83	2.54	2.955 (4)	112

Symmetry codes: (iv) ; (vi) .

supplementary crystallographic information

Comment

With increasing interest in microporous materials, the synthesis of compounds like borophosphates with open framework structures have drawn much attention during the past few years. These compounds show a rich crystal chemistry (Kniep et al., 1998; Ewald et al., 2007).

The crystal structure of LiNi(H₂O)₂[BP₂O₈]^_.H₂O is isotypic with that of the Mg analogue (Lin et al. 2008) and contains an infinite one-dimensional anionic structure. The condensation of BO₄ and PO₄ tetrahedra leads to helical ribbons with composition [BP₂O₈]^3- (Fig. 1), whereby each BO₄ tetrahedron shares its vertices with four PO₄ tetrahedra. Bond lenghts and angles within the anionic structure are consistent with related borophosphates (Boy & Kniep, 2001; Lin et al., 2008).

The free loop of the borophosphate helix is occupied by Li⁺ cations, which are coordinated by with five O atoms, two from phosphate groups (O2) and three from water molecules (O3), thus completing an helical unit {Li[BP₂O₈]^2-} with a central channel running along the 6₅ screw axis. The channels are filled up with water of crystallization (O6). The Ni²⁺ cations, located on a twofold rotation axis, are surrounded in a distorted octahedral coordination by four O atoms from adjacent phosphate groups and two water molecules, leading to the overall formula LiNi(H₂O)₂[BP₂O₈]_^.H₂O (Fig. 2). The Ni—O distances range from 2.048 (3)–2.130 (3) Å and are in the usual range. The crystal structure is stabilized by O—H···O hydrogen bonds between coordinated or uncoordinated water molecules and O atoms that are part of the helices.

Experimental

Green block-shaped crystals were synthesized hydrothermally from a mixture of Ni(NO₃)₂, Li₂B₄O₇, water and H₃PO₄. In a typical synthesis, 0.87 g Ni(NO₃)_2^.6H₂O was dissolved in a mixture of 5 mL water, 1.691 g Li₂B₄O₇ and 2 ml H₃PO₄ (85%_wt ) under constant stirring. Finally, the mixture was kept in a 30 ml Teflon-lined steel autoclave at 443 K for 6d. The autoclave was slowly cooled to room temperature.

Refinement

The highest peak in the difference map is 1.29Å from atom H6, and the minimum peak is 0.48Å from atom P2.

Figures

Fig. 1.

A part of the structure of LiNi(H2O)2[BP2O8].H2O with displacement ellipsoids drawn at the 50% the probability level. Symmetry codes: (i) 1 - y, 1 - x, 0.16667 - z; (ii) 1 - x, 1 - x + y, 0.33333 - z; (iii) x-y, x, -0.16667 + z; (iv) y, x, 0.66667 - z; (v) y, -x + y, 0.16667 + z; (vi) x, x-y, 0.83333 - z.

Fig. 2.

Polyhedral diagram for LiNi(H2O)2[BP2O8].H2O in projection along [001]. Colour code: purple P, orange B, blue Ni, red OW6 and green Li.

Crystal data

LiNi(H2O)2[BP2O8]·H2O	Dx = 2.686 Mg m−3
Mr = 320.44	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6522	Cell parameters from 1684 reflections
Hall symbol: P 65 2 ( 0	θ = 2.5–29.5°
a = 9.3359 (3) Å	µ = 2.91 mm−1
c = 15.7497 (11) Å	T = 296 K
V = 1188.82 (10) Å3	Block, green
Z = 6	0.22 × 0.20 × 0.17 mm
F(000) = 960

Data collection

Bruker APEXII CCD area-detector diffractometer	708 independent reflections
Radiation source: fine-focus sealed tube	684 reflections with I > 2σ(I)
graphite	Rint = 0.049
φ and ω scans	θmax = 29.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −10→11
Tmin = 0.567, Tmax = 0.638	k = −8→11
6139 measured reflections	l = −18→14

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.026	H-atom parameters constrained
wR(F2) = 0.065	w = 1/[σ2(Fo2) + (0.0284P)2 + 2.1868P] where P = (Fo2 + 2Fc2)/3
S = 1.14	(Δ/σ)max = 0.001
708 reflections	Δρmax = 0.68 e Å−3
75 parameters	Δρmin = −0.39 e Å−3
0 restraints	Absolute structure: Flack (1983), 235 Friedel pairs
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.01 (3)

Special details

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

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R– factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Ni1	0.55533 (4)	0.44467 (4)	0.0833	0.0098 (2)
P2	0.38859 (12)	0.21675 (12)	0.24795 (7)	0.0093 (3)
O5	0.4156 (3)	0.2355 (3)	0.34570 (16)	0.0108 (6)
O4	0.2137 (3)	0.1899 (4)	0.23106 (18)	0.0129 (7)
O3	0.4865 (4)	0.1970 (4)	0.05090 (19)	0.0214 (7)
O2	0.5200 (4)	0.3782 (3)	0.21028 (17)	0.0142 (7)
O1	0.3853 (4)	0.0644 (4)	0.21452 (17)	0.0151 (7)
O6	0.2044 (10)	0.1022 (5)	−0.0833	0.079 (2)
B	0.3037 (8)	0.1518 (4)	0.4167	0.0090 (13)
Li	0.466 (3)	0.2331 (13)	−0.0833	0.080 (5)
H3A	0.5738	0.2196	0.0284	0.096*
H6	0.1509	0.0382	−0.1223	0.096*
H3B	0.4428	0.1571	0.0973	0.096*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Ni1	0.0098 (3)	0.0098 (3)	0.0100 (3)	0.0050 (3)	0.0013 (3)	0.0013 (3)
P2	0.0097 (5)	0.0097 (5)	0.0086 (5)	0.0050 (4)	0.0015 (4)	0.0015 (4)
O5	0.0095 (14)	0.0126 (16)	0.0089 (13)	0.0044 (12)	0.0014 (11)	0.0016 (11)
O4	0.0131 (16)	0.0132 (15)	0.0157 (16)	0.0091 (13)	−0.0022 (12)	−0.0030 (12)
O3	0.0277 (18)	0.0162 (18)	0.0231 (17)	0.0130 (14)	0.0121 (14)	0.0049 (14)
O2	0.0143 (16)	0.0134 (14)	0.0101 (13)	0.0032 (13)	0.0021 (12)	0.0040 (11)
O1	0.0211 (17)	0.0159 (16)	0.0147 (14)	0.0140 (14)	0.0008 (14)	−0.0017 (12)
O6	0.083 (6)	0.061 (3)	0.100 (6)	0.042 (3)	0.000	−0.024 (4)
B	0.012 (3)	0.009 (2)	0.007 (3)	0.0059 (15)	0.000	0.001 (2)
Li	0.094 (15)	0.089 (10)	0.058 (10)	0.047 (8)	0.000	0.011 (10)

Geometric parameters (Å, °)

Ni1—O1i	2.048 (3)	O4—Bi	1.471 (5)
Ni1—O1ii	2.048 (3)	O3—Li	2.164 (4)
Ni1—O2iii	2.070 (3)	O2—Liiv	2.113 (13)
Ni1—O2	2.070 (3)	O1—Ni1v	2.048 (3)
Ni1—O3	2.130 (3)	O6—Li	2.12 (2)
Ni1—O3iii	2.130 (3)	B—O5vi	1.461 (5)
Ni1—Li	3.137 (5)	B—O4vii	1.471 (5)
Ni1—Liiv	3.137 (5)	B—O4v	1.471 (5)
P2—O1	1.503 (3)	Li—O2iii	2.113 (13)
P2—O2	1.510 (3)	Li—O2viii	2.113 (13)
P2—O4	1.546 (3)	Li—O3ix	2.164 (4)
P2—O5	1.556 (3)	Li—Ni1viii	3.137 (5)
O5—B	1.461 (5)
O1i—Ni1—O1ii	92.58 (18)	B—O5—P2	131.6 (3)
O1i—Ni1—O2iii	88.53 (11)	Bi—O4—P2	127.8 (3)
O1ii—Ni1—O2iii	101.19 (12)	Ni1—O3—Li	93.87 (18)
O1i—Ni1—O2	101.19 (12)	P2—O2—Ni1	127.36 (17)
O1ii—Ni1—O2	88.53 (11)	P2—O2—Liiv	129.2 (4)
O2iii—Ni1—O2	166.00 (17)	Ni1—O2—Liiv	97.1 (2)
O1i—Ni1—O3	86.52 (13)	P2—O1—Ni1v	140.72 (18)
O1ii—Ni1—O3	177.55 (12)	O5vi—B—O5	103.4 (4)
O2iii—Ni1—O3	81.08 (11)	O5vi—B—O4vii	111.43 (15)
O2—Ni1—O3	89.40 (11)	O5—B—O4vii	114.16 (15)
O1i—Ni1—O3iii	177.55 (12)	O5vi—B—O4v	114.16 (15)
O1ii—Ni1—O3iii	86.52 (13)	O5—B—O4v	111.43 (16)
O2iii—Ni1—O3iii	89.40 (11)	O4vii—B—O4v	102.6 (4)
O2—Ni1—O3iii	81.08 (11)	O2iii—Li—O2viii	106.9 (9)
O3—Ni1—O3iii	94.47 (19)	O2iii—Li—O6	126.5 (5)
O1i—Ni1—Li	72.0 (4)	O2viii—Li—O6	126.5 (5)
O1ii—Ni1—Li	138.23 (8)	O2iii—Li—O3	79.3 (3)
O2iii—Ni1—Li	41.9 (3)	O2viii—Li—O3	95.5 (4)
O2—Ni1—Li	131.83 (17)	O6—Li—O3	94.3 (6)
O3—Ni1—Li	43.50 (9)	O2iii—Li—O3ix	95.5 (4)
O3iii—Ni1—Li	107.3 (4)	O2viii—Li—O3ix	79.3 (3)
O1i—Ni1—Liiv	138.23 (8)	O6—Li—O3ix	94.3 (6)
O1ii—Ni1—Liiv	72.0 (4)	O3—Li—O3ix	171.3 (11)
O2iii—Ni1—Liiv	131.83 (17)	O2iii—Li—Ni1	40.91 (9)
O2—Ni1—Liiv	41.9 (3)	O2viii—Li—Ni1	118.8 (6)
O3—Ni1—Liiv	107.3 (4)	O6—Li—Ni1	103.3 (4)
O3iii—Ni1—Liiv	43.50 (9)	O3—Li—Ni1	42.64 (13)
Li—Ni1—Liiv	143.2 (5)	O3ix—Li—Ni1	134.5 (3)
O1—P2—O2	115.38 (17)	O2iii—Li—Ni1viii	118.8 (6)
O1—P2—O4	105.45 (17)	O2viii—Li—Ni1viii	40.91 (9)
O2—P2—O4	111.07 (18)	O6—Li—Ni1viii	103.3 (4)
O1—P2—O5	112.24 (16)	O3—Li—Ni1viii	134.5 (4)
O2—P2—O5	105.75 (16)	O3ix—Li—Ni1viii	42.64 (13)
O4—P2—O5	106.70 (15)	Ni1—Li—Ni1viii	153.4 (7)

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

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O5viii	0.81	2.01	2.746 (4)	151
O3—H3A···O2viii	0.81	2.60	3.165 (4)	128
O6—H6···O4x	0.83	2.52	3.331 (4)	167
O6—H6···O1x	0.83	2.66	3.092 (4)	114
O3—H3B···O1	0.83	2.00	2.810 (4)	167
O3—H3B···O2	0.83	2.54	2.955 (4)	112

Symmetry codes: (viii) −y+1, x−y, z−1/3; (x) x−y, −y, −z.