Change search
ReferencesLink to record
Permanent link

Direct link
Structural and Vibrational Properties of Silyl (SiH3-) Anions in KSiH3 and RbSiH3: New Insight into Si-H Interactions
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Show others and affiliations
2015 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 54, no 5, 2300-2309 p.Article in journal (Refereed) Published
Abstract [en]

The alkali metal silyl hydrides ASiH(3) (A = K, Rb) and their deuteride analogues were prepared from the Zintl phases ASi. The crystal structures of ASiH(3) consist of metal cations and pyramidal SiH3 ions. At room temperature SiH3 moieties are randomly oriented (alpha modifications). At temperatures below 200 K ASiH(3) exist as ordered low-temperature (beta) modifications. Structural and vibrational properties of SiH3- in ASiH(3) were characterized by a combination of neutron total scattering experiments, infrared and Raman spectroscopy, as well as density functional theory calculations. In disordered alpha-ASiH(3) SiH3 ions relate closely to freely rotating moieties with C(3)v symmetry (Si-H bond length = 1.52 angstrom; HSiH angle 92.2 degrees). Observed stretches and bends are at 1909/1903 cm(-1) (nu(1), A(1)), 1883/1872 cm(-1) (nu(3), E), 988/986 cm(-1) (nu(4), E), and 897/894 cm(-1) (nu(2), A(1)) for A = K/Rb. In ordered beta-ASiH(3) silyl anions are slightly distorted with respect to their ideal C-3v symmetry. Compared to a-ASiH(3) the molar volume is by about 15% smaller and the SiH stretching force constant is reduced by 4%. These peculiarities are attributed to reorientational dynamics of SiH3 anions in a-ASiH(3). SiH stretching force constants for SiH3 moieties in various environments fall in a range from 1.9 to 2.05 N cm(-1). These values are considerably smaller compared to silane, SiH4 (2.77 N cm(-1)). The reason for the drastic reduction of bond strength in SiH3- remains to be explored.

Place, publisher, year, edition, pages
2015. Vol. 54, no 5, 2300-2309 p.
National Category
Chemical Sciences
URN: urn:nbn:se:su:diva-116698DOI: 10.1021/ic502931eISI: 000350391600027PubMedID: 25668724OAI: diva2:807377


Available from: 2015-04-23 Created: 2015-04-23 Last updated: 2015-04-23Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Häussermann, Ulrich
By organisation
Department of Materials and Environmental Chemistry (MMK)
In the same journal
Inorganic Chemistry
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 43 hits
ReferencesLink to record
Permanent link

Direct link