Vibrational Properties of Polyanionic Hydrides SrAl2H2 and SrAlSiH: New Insights into Al-H Bonding Interactions

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• 作者：Myeong H. Lee ; Otto F. Sankey ; Thomas Bj&ouml ; rling ; David Moser ; Dag Noré ; us ; Stewart F. Parker ; Ulrich Hä ; ussermann
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：August 20, 2007
• 年：2007
• 卷：46
• 期：17
• 页码：6987 - 6991
• 全文大小：173K
• 年卷期：v.46,no.17(August 20, 2007)
• ISSN：1520-510X

文摘

The vibrational properties of the recently discovered aluminum hydrides SrAl₂H₂ and SrAlSiH have been investigatedby means of inelastic neutron scattering (INS) and first-principles calculations. Both compounds contain Al-H unitsbeing part of a two-dimensional polyanionic layer, [(AlH)(AlH)]^2- and [Si(AlH)]^2-, respectively. The INS spectrumof SrAlSiH is characterized by very weakly dispersed Al-H modes with well-resolved overtones, while SrAl₂H₂yields a solid-state dispersed phonon spectrum. The frequency of the stretching mode of the Al-H unit in SrAlSiHis the hitherto lowest observed for a terminal Al-H bond. At the same time, SrAlSiH displays the highest decompositiontemperature known for an aluminum hydride compound. It is proposed that the stability of solid-state aluminumhydrides correlates inversely with the strength of Al-H bonding.