Hexabromo‐ and hexaiododisilane: small and simple molecules showing completely different crystal structures. Issue 11 (23rd October 2014)

• Record Type: Journal Article
• Authors: Berger, Matthias; Auner, Norbert; Bolte, Michael
• Is Part Of: Acta crystallographica. Volume 70:Issue 11(2014:Nov.)
• Page Start: 1088
• Page End: 1091
• Publication Date: 2014-10-23
• Subjects: Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229614022992
• Languages: English
• ISSNs: 2053-2296

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The title compounds were prepared through dephenylation of hexaphenyldisilane with acetyl bromide or acetyl iodide in the presence of the corresponding aluminium halide. Both substances were purified <italic>via</italic> sublimation and, for the first time, single crystals of hexabromodisilane, Si<sub>2</sub>Br<sub>6</sub>, and a new polymorph of hexaiododisilane, Si<sub>2</sub>I<sub>6</sub>, could be isolated. Molecules of Si<sub>2</sub>Br<sub>6</sub> are located on a special position of site symmetry 2/<italic>m</italic> with a quarter of a molecule in the asymmetric unit. Molecules of Si<sub>2</sub>I<sub>6</sub> are located on a special position of site symmetry <inline-graphic xlink:href="ark:/27927/pgh24sdzqqc" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> with a sixth of a molecule in the asymmetric unit. The bond lengths of Si<sub>2</sub>Br<sub>6</sub> and Si<sub>2</sub>I<sub>6</sub> are in the usual ranges and both molecules adopt a staggered conformation. It is interesting to note that Si<sub>2</sub>Br<sub>6</sub> and Si<sub>2</sub>I<sub>6</sub> do not form isomorphous structures. Moreover, an orthorhombic polymorph of the present structure of Si<sub>2</sub>I<sub>6</sub> is already known [Jansen & Friede (1996). <italic>Acta Cryst.</italic> C<bold>52</bold>, 1333–1334]. Although the title compounds feature such small and simple molecules they show completely different crystal structures.</p> </abstract>