In:
Acta Crystallographica Section B Structural Science, International Union of Crystallography (IUCr), Vol. 58, No. 1 ( 2002-02-01), p. 52-61
Abstract:
The compounds tetrakis(trimethylstannyl)germane, Ge(SnMe 3 ) 4 (1), and tetrakis(trimethylstannyl)silane, Si(SnMe 3 ) 4 (2), have crystal structures with the quasispherical molecules in a closed-packed stacking. At room temperature both structures have the space group P \bar 1 ( Z = 2) with a = 9.94457 (5), b = 14.52927 (8), c = 9.16021 (5) Å, α = 90.53390 (30), β = 111.73080 (30), γ = 90.0049 (4)°, and V = 1229.414 (12) Å 3 for (1) and a = 9.92009 (7), b = 14.51029 (11), c = 9.13585 (7) Å, α = 90.4769 (4), β = 111.6724 (4), γ = 89.9877 (6)°, and V = 1222.037 (16) Å 3 for (2). The molecules are found to be ordered as a result of steric interactions between neighboring molecules, as shown by analyzing the distances between the atoms. Upon heating, both compounds undergo a first-order phase transition at temperatures T c = 348 ± 5 K, as characterized by a relative jump of the lattice parameter of ∼16%. At 353 K, both structures have the space group P \bar 1 ( Z = 4), with a = 14.2037 (2) Å, and V = 2865.52 (7) Å 3 for (1) and a = 14.1346 (2) Å, and V = 2823.90 (7) Å 3 for (2). Rietveld refinements were performed for the low-temperature phases measured at T = 295 K [ R wp = 0.0844 for (1), R wp = 0.0940 for (2)] and for the high-temperature phases measured at T = 353 K [ R wp = 0.0891 for (1), R wp = 0.0542 for (2)]. The combination of high-resolution X-ray powder diffraction measurements and variable-temperature magic-angle-spinning 13 C, 29 Si and 119 Sn NMR experiments demonstrates low crystallographic and molecular ( C 1 ) symmetries for the low-temperature phases of (1) and (2) at temperatures T 〈 348 ± 5 K and high crystallographic symmetry due to rotational disorder for the high-temperature phases at temperatures T 〉 348 ± 5 K.
Type of Medium:
Online Resource
ISSN:
0108-7681
DOI:
10.1107/S0108768101016688
DOI:
10.1107/S0108768101016688/os0078sup1.cif
DOI:
10.1107/S0108768101016688/os0078sisnmesup2.rtv
DOI:
10.1107/S0108768101016688/os0078gesnmesup3.rtv
Language:
Unknown
Publisher:
International Union of Crystallography (IUCr)
Publication Date:
2002
detail.hit.zdb_id:
2020841-8
SSG:
13
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