Structural phase stability studies on MBeH3 (M = Li, Na, K, Rb, Cs) from density functional calculations

P Vajeeston; P Ravindran; H Fjellvåg

doi:10.1021/ic7015897

Structural phase stability studies on MBeH3 (M = Li, Na, K, Rb, Cs) from density functional calculations

Inorg Chem. 2008 Jan 21;47(2):508-14. doi: 10.1021/ic7015897. Epub 2007 Dec 19.

Authors

P Vajeeston¹, P Ravindran, H Fjellvåg

Affiliation

¹ Department of Chemistry, Center for Materials Sciences and Nanotechnology, University of Oslo, Box 1033 Blindern, N-0315 Oslo, Norway. ponniahv@kjemi.uio.no

PMID: 18088114
DOI: 10.1021/ic7015897

Abstract

Density functional theory calculations within the generalized-gradient approximation are used to establish the ground-state structure, equilibrium structural parameters, and electronic structure for MBeH(3) phases. From the 24 structural arrangements used as inputs for structural optimization calculations, the ground-state crystal structures of MBeH(3) phases have been predicted. At ambient conditions, LiBeH(3) and NaBeH(3) crystallize with perovskite-related orthorhombic and cubic structures, respectively. The remaining phases KBeH(3), RbBeH(3), and CsBeH(3) crystalize in a monoclinic structure. In the predicted phases one can store up to 15.93 wt % of hydrogen. The formation energy for the MBeH(3) phases have been investigated along different reaction pathways. The electronic structures reveal that all these phases are insulators with estimated band gaps varying between 1.79 and 3.44 eV.