Solid-state structures of the covalent hydrides germane and stannane

The low-temperature crystal structures of perdeuterogermane (m.p. 108 K) and perdeuterostannane (m.p. 123 K) are reported. The structures have been characterized from low-temperature (5 K) high-resolution neutron powder diffraction experiments following sample preparation using in situ gas-condensation techniques. GeD₄ crystallizes in an ortho­rhombic structure, space group P2₁2₁2₁, with one molecule in the asymmetric unit, and with an average Ge-D bond length of 1.517 (3) Å. The SnD₄ structure is monoclinic (space group C2/c), and the molecule is located on a twofold rotation axis with an average Sn-D bond length of 1.706 (3) Å. The crystal structures are discussed in relation to those of other tetrahedral molecules of group IV hydrides at low temperature, and evidence is presented that the crystal structure of silane, below 38 K, is isostructural with germane.

Computing details

For both compounds, data collection: ISIS instrument control program (ICP); cell refinement: TOPAS-Academic (Coehlo); data reduction: Standard HRPD normalisation routines; program(s) used to refine structure: TOPAS.

Figures

(GeD4_5K) perdeuterogermane

Crystal data

D4Ge	Z = 4
Mr = 80.65	Dx = 1.966 Mg m^−3
Orthorhombic, P212121	Melting point: 108 K
Hall symbol: P 2ac 2ab	Time-of-flight neutron radiation, λ = 1.24-5.36 Å
a = 7.35565 (17) Å	T = 5 K
b = 8.15934 (11) Å	Particle morphology: irregular powder
c = 4.53932 (11) Å	cylinder, 25 × 11 mm
V = 272.44 (1) Å^3

Data collection

HRPD diffractometer	Scan method: tof 30-130 ms
Specimen mounting: standard cylindrical vanadium sample holder

Refinement

Least-squares matrix: full	Profile function: TOPAS TOF Pseudo-Voigt Profile function
Rp = 0.061	45 parameters
Rwp = 0.069	0 restraints
Rexp = 0.043	0 constraints
R(F^2) = 0.15705	Weighting scheme based on measured s.u.'s
χ^2 = 2.560	(Δ/σ)max = 0.01
? data points	Background function: Shifted Chebyshev function (10 terms)
Excluded region(s): None	Preferred orientation correction: Spherical Harmonic ODF Spherical harmonic order= 6 The sample symmetry is: cylindrical (fiber texture) Index = 2 0 0 Coeff= 0.3104 Index = 2 0 2 Coeff= 0.9511 Index = 4 0 0 Coeff= 0.2995 Index = 4 0 2 Coeff= -0.2573 Index = 4 0 4 Coeff= -0.2003 Index = 6 0 0 Coeff= -0.7728 Index = 6 0 2 Coeff= -0.5283 Index = 6 0 4 Coeff= -0.4214 Index = 6 0 6 Coeff= 0.6972 Prefered orientation correction range: Min= 0.49389, Max= 1.59951

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

	x	y	z	Uiso*/Ueq
Ge	0.4922 (5)	0.3536 (3)	0.3559 (5)	0.0028 (5)*
D1	0.6327 (7)	0.3211 (4)	0.1148 (11)	0.0391 (11)*
D2	0.3175 (8)	0.4062 (6)	0.1989 (10)	0.0470 (14)*
D3	0.4605 (7)	0.2034 (4)	0.5311 (10)	0.0407 (13)*
D4	0.5513 (6)	0.4954 (6)	0.5539 (10)	0.0455 (15)*

Geometric parameters (Å, º)

Ge—D1	1.528 (5)	Ge—D3	1.480 (5)
Ge—D2	1.531 (6)	Ge—D4	1.528 (6)
D1—Ge—D2	106.4 (3)	D2—Ge—D3	110.4 (2)
D1—Ge—D3	110.3 (2)	D2—Ge—D4	107.4 (3)
D1—Ge—D4	111.1 (3)	D3—Ge—D4	110.8 (2)

(SnD4_5K) perdeuterostannane

Crystal data

D4Sn	V = 308.22 (1) Å^3
Mr = 126.75	Z = 4
Monoclinic, C2/c	Dx = 2.731 Mg m^−3
Hall symbol: -C 2yc	Melting point: 123 K
a = 8.87431 (14) Å	Time-of-flight neutron radiation, λ = 1.24-5.36 Å
b = 4.54743 (7) Å	T = 5 K
c = 8.75705 (12) Å	Particle morphology: irregular powder
β = 119.2882 (10)°	cylinder, 25 × 11 mm

Data collection

HRPD diffractometer	Scan method: tof 30-130 ms
Specimen mounting: standard cylindrical vanadium sample holder

Refinement

Least-squares matrix: full	Profile function: TOPAS TOF Pseudo-Voigt Profile function
Rp = 0.111	35 parameters
Rwp = 0.124	0 restraints
Rexp = 0.062	0 constraints
R(F^2) = 0.13390	Weighting scheme based on measured s.u.'s
χ^2 = 4.121	(Δ/σ)max = 0.02
? data points	Background function: Shifted Chebyshev function (10 terms)
Excluded region(s): None	Preferred orientation correction: Spherical Harmonic ODF Spherical harmonic order= 4 The sample symmetry is: cylindrical (fiber texture) Index = 2 0 -2 Coeff= -0.1205 Index = 2 0 0 Coeff= -0.0792 Index = 2 0 2 Coeff= -0.0205 Index = 4 0 -4 Coeff= 0.1646 Index = 4 0 -2 Coeff= 0.4387 Index = 4 0 0 Coeff= -0.4362 Index = 4 0 2 Coeff= 0.2127 Index = 4 0 4 Coeff= -0.0198 Prefered orientation correction range: Min= 0.81761, Max= 1.29987

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

	x	y	z	Uiso*/Ueq
Sn	0.5	0.4258 (5)	0.25	0.0049 (8)*
D1	0.3237 (3)	0.6461 (4)	0.1965 (4)	0.0302 (8)*
D2	0.5351 (3)	0.2142 (5)	0.4235 (3)	0.0276 (8)*

Geometric parameters (Å, º)

Sn—D1	1.719 (3)	Sn—D2	1.693 (3)
Sn—D1^i	1.719 (3)	Sn—D2^i	1.693 (3)
D1—Sn—D1^i	108.7 (2)	D1^i—Sn—D2	110.07 (11)
D1—Sn—D2	108.63 (14)	D1^i—Sn—D2^i	108.63 (14)
D1—Sn—D2^i	110.07 (11)	D2—Sn—D2^i	110.7 (2)

Symmetry code: (i) −x+1, y, −z+1/2.