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Hydro­thermally prepared dilithium tin hexa­hydro­xide crystallizes in the monoclinic system (space group P21/n), with the Sn atom at a site with \overline 1 symmetry and all other atoms in general positions. The Sn coordination polyhedron is made up of six hydro­xide groups. The Li atom is tetrahedrally coordinated by oxy­gen, with the tetrahedra sharing two corners and one edge with the adjacent Sn octahedra. Hydro­gen bonds between the OH groups provide additional bonds in the framework.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100018710/br1309sup1.cif
Contains datablocks general, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100018710/br1309Isup2.hkl
Contains datablock I

Comment top

Recently, there has been much interest in tin oxide compounds as anodes in high energy density lithium batteries (Idota et al., 1997; Courtney & Dahn, 1997; Goward et al., 1999). In a search for new anode materials and in trying to understand the reduction mechanism of tin oxides, a systematic study of lithium tin oxides has been made by our group. This work presents the crystal structure of a new lithium tin hydroxide, Li2Sn(OH)6, resulting from this study.

The title structure is built up from slightly distorted Li tetrahedra and Sn octahedra (Fig. 1). Each Li tetrahedron shares two corners and one edge with three Sn octahedra (Fig. 2) to form a network. On the other hand, each Sn octahedron that lies on the center of symmetry shares two coplanar edges (O1—O2) and two corners (O3) to form a chain along the a axis. Two corners (O2) of the Sn octahedron are also shared with the Li tetrahedra even though they are already involved in the edge-sharing. The Sn—O2—Li-sharing links the chains into a three-dimensional network. Three hydrogen bonds (Table 2) between the OH groups form additional links in the network.

This structure is related to the hydrated lithium tin hydroxide compound, Li2[Sn(OH)6]·2H2O, reported previously by Reuter & Bargon (1997). It crystallizes in space group P21/n, with a = 5.023 (1), b = 6.923 (1) and c = 10.202 (3) Å, and β = 99.78 (1)°. In contrast with the title compound, there is no edge-sharing in the hydrate, where each Li tetrahedron shares three corners with Sn octahedra to form a three-dimensional framework. The forth corner is occupied by a water molecule (Fig. 3). The presence of these water groups increases the unit cell volume from the 257.6 Å3 in the title compound to 349.6 Å3 in the hydrate.

An Li2Sn(OH)6 material reported by Nakata & Toyooka (1997) also crystallizes in space group P21/n, with a = 10.2016 (5), b = 6.9246 (3) and c = 5.0255 (2) Å, and β=99.764 (3)°. Interestingly, the cell dimensions for this compound are essentially the same as those for the above-mentioned crystallohydrate (a and c axes are switched). This structure was solved using powder diffraction data and can be converted to the previous structure. However, while Sn and three O atoms convert to the same type of atoms, Li atoms convert to the O atoms of the water molecule. Thus the water molecule was misinterpreted as Li.

Related literature top

For related literature, see: Courtney & Dahn (1997); Goward et al. (1999); Idota et al. (1997); Nakata & Toyooka (1997); Reuter & Bargon (1997).

Experimental top

The title compound was prepared by hydrothermal treatment of SnO (Fisher) and LiOH (Aldrich) in a molar ratio of 1:3. The LiOH solution was prepared and then mixed with SnO powder and stirred for 5 min. The cloudy liquid was transferred to a Parr reactor and heated at 443 K for 3 d. The solution was cooled and filtered, and white crystals of Li2Sn(OH)6 were separated manually from the gray powder and dried at 330 K for 5 h.

Refinement top

All Sn and O atoms were located from the electron-density map. The Li atom and remaining H atoms were located from the difference Fourier maps.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and ATOMS (Dowty, 1999); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The structure of Li2Sn(OH)6, with displacement ellipsoids at the 50% probability level. Symmetry codes: (i) -x, 1 - y, 1 - z; (ii) 1/2 - x, y - 1/2, 1/2 - z; (iii) x - 1/2, 3/2 - y, 1/2 + z; (iv) 1 - x, 1 - y, 1 - z; (v) x - 1, y, z.
[Figure 2] Fig. 2. The three-dimensional structure of Li2Sn(OH)6. Sn(OH)6 are shown as octahedra and Li atoms as balls.
[Figure 3] Fig. 3. The structure of Li2[Sn(OH)6]·2H2O. Sn(OH)6 are shown as octahedra, and Li atoms (crossed) and water molecule are shown as balls.
Dilithium tin(VI) hexahydroxide top
Crystal data top
Li2Sn(OH)6F(000) = 220
Mr = 234.62Dx = 3.024 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 5.1640 (6) ÅCell parameters from 929 reflections
b = 5.4013 (7) Åθ = 8–57°
c = 9.2982 (11) ŵ = 4.90 mm1
β = 96.596 (2)°T = 293 K
V = 257.63 (5) Å3Irregular, colorless
Z = 20.12 × 0.08 × 0.06 mm
Data collection top
Bruker SMART Apex CCD
diffractometer
617 independent reflections
Radiation source: fine-focus sealed tube547 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
ω scansθmax = 28.8°, θmin = 4.3°
Absorption correction: ψ-scan
(SADABS; Sheldrick, 1996)
h = 66
Tmin = 0.65, Tmax = 0.75k = 57
1511 measured reflectionsl = 1112
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.017All H-atom parameters refined
wR(F2) = 0.041 w = 1/[σ2(Fo2) + (0.0167P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
617 reflectionsΔρmax = 0.85 e Å3
56 parametersΔρmin = 0.50 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0132 (18)
Crystal data top
Li2Sn(OH)6V = 257.63 (5) Å3
Mr = 234.62Z = 2
Monoclinic, P21/nMo Kα radiation
a = 5.1640 (6) ŵ = 4.90 mm1
b = 5.4013 (7) ÅT = 293 K
c = 9.2982 (11) Å0.12 × 0.08 × 0.06 mm
β = 96.596 (2)°
Data collection top
Bruker SMART Apex CCD
diffractometer
617 independent reflections
Absorption correction: ψ-scan
(SADABS; Sheldrick, 1996)
547 reflections with I > 2σ(I)
Tmin = 0.65, Tmax = 0.75Rint = 0.033
1511 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0170 restraints
wR(F2) = 0.041All H-atom parameters refined
S = 1.06Δρmax = 0.85 e Å3
617 reflectionsΔρmin = 0.50 e Å3
56 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
Sn01/21/20.00939 (13)
O10.2180 (4)0.6013 (4)0.3381 (2)0.0141 (4)
O20.2822 (4)0.2304 (4)0.5395 (2)0.0152 (4)
O30.2221 (4)0.7324 (3)0.6360 (2)0.0146 (4)
Li0.0964 (9)0.7626 (9)0.1589 (5)0.0192 (10)
H10.318 (7)0.659 (7)0.367 (4)0.024 (11)*
H20.246 (6)0.122 (6)0.547 (4)0.011 (10)*
H30.183 (6)0.747 (6)0.707 (4)0.026 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sn0.00971 (17)0.00941 (17)0.00917 (17)0.00009 (8)0.00158 (9)0.00036 (8)
O10.0136 (10)0.0166 (11)0.0124 (9)0.0030 (9)0.0024 (8)0.0012 (8)
O20.0162 (10)0.0087 (10)0.0208 (11)0.0009 (8)0.0023 (8)0.0023 (9)
O30.0164 (10)0.0165 (10)0.0114 (10)0.0036 (7)0.0035 (7)0.0036 (8)
Li0.014 (2)0.023 (2)0.021 (2)0.0016 (19)0.0027 (18)0.002 (2)
Geometric parameters (Å, º) top
Sn—O32.0388 (19)O1—Liii2.064 (5)
Sn—O3i2.0388 (19)O2—Liii2.023 (5)
Sn—O12.055 (2)O3—Liiii1.921 (5)
Sn—O1i2.055 (2)Li—O11.920 (5)
Sn—O22.063 (2)Li—O3iv1.921 (5)
Sn—O2i2.063 (2)Li—O2v2.023 (5)
O1—Li1.920 (5)Li—O1v2.064 (5)
O3i—Sn—O3180.0O1i—Sn—O2i83.30 (8)
O3i—Sn—O191.49 (8)O2—Sn—O2i180.000 (1)
O3—Sn—O188.51 (8)Li—O1—Sn127.19 (17)
O3i—Sn—O1i88.51 (8)Li—O1—Liii121.24 (17)
O3—Sn—O1i91.49 (8)Sn—O1—Liii92.68 (15)
O1—Sn—O1i180.000 (1)Liii—O2—Sn93.63 (16)
O3i—Sn—O290.65 (8)Liiii—O3—Sn124.39 (18)
O3—Sn—O289.35 (8)O1—Li—O3iv109.1 (2)
O1—Sn—O283.30 (8)O1—Li—O2v130.3 (3)
O1i—Sn—O296.70 (8)O3iv—Li—O2v108.3 (2)
O3i—Sn—O2i89.35 (8)O1—Li—O1v106.6 (2)
O3—Sn—O2i90.65 (8)O3iv—Li—O1v116.7 (3)
O1—Sn—O2i96.70 (8)O2v—Li—O1v84.05 (19)
Symmetry codes: (i) x, y+1, z+1; (ii) x+1/2, y1/2, z+1/2; (iii) x+1/2, y+3/2, z+1/2; (iv) x1/2, y+3/2, z1/2; (v) x+1/2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2vi0.64 (4)2.23 (4)2.847 (3)165 (4)
O2—H2···O3vii0.62 (3)2.27 (3)2.864 (3)161 (4)
O3—H3···O2viii0.72 (4)2.34 (4)3.020 (3)158 (3)
Symmetry codes: (vi) x+1, y+1, z+1; (vii) x, y1, z; (viii) x+1/2, y+1/2, z+3/2.

Experimental details

Crystal data
Chemical formulaLi2Sn(OH)6
Mr234.62
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)5.1640 (6), 5.4013 (7), 9.2982 (11)
β (°) 96.596 (2)
V3)257.63 (5)
Z2
Radiation typeMo Kα
µ (mm1)4.90
Crystal size (mm)0.12 × 0.08 × 0.06
Data collection
DiffractometerBruker SMART Apex CCD
diffractometer
Absorption correctionψ-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.65, 0.75
No. of measured, independent and
observed [I > 2σ(I)] reflections
1511, 617, 547
Rint0.033
(sin θ/λ)max1)0.678
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.017, 0.041, 1.06
No. of reflections617
No. of parameters56
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.85, 0.50

Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and ATOMS (Dowty, 1999), SHELXL97.

Selected bond lengths (Å) top
Sn—O32.0388 (19)Li—O3i1.921 (5)
Sn—O12.055 (2)Li—O2ii2.023 (5)
Sn—O22.063 (2)Li—O1ii2.064 (5)
Li—O11.920 (5)
Symmetry codes: (i) x1/2, y+3/2, z1/2; (ii) x+1/2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2iii0.64 (4)2.23 (4)2.847 (3)165 (4)
O2—H2···O3iv0.62 (3)2.27 (3)2.864 (3)161 (4)
O3—H3···O2v0.72 (4)2.34 (4)3.020 (3)158 (3)
Symmetry codes: (iii) x+1, y+1, z+1; (iv) x, y1, z; (v) x+1/2, y+1/2, z+3/2.
 

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