Gd(5)Si(4-x)P(x): targeted structural changes through increase in valence electron count

Volodymyr Svitlyk; Gordon J Miller; Yurij Mozharivskyj

doi:10.1021/ja8085033

Gd(5)Si(4-x)P(x): targeted structural changes through increase in valence electron count

J Am Chem Soc. 2009 Feb 18;131(6):2367-74. doi: 10.1021/ja8085033.

Authors

Volodymyr Svitlyk¹, Gordon J Miller, Yurij Mozharivskyj

Affiliation

¹ Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.

PMID: 19199627
DOI: 10.1021/ja8085033

Abstract

Phase transformations in the Gd(5)Si(4-x)P(x) system (0 <or= x <or= 2), studied through X-ray diffraction techniques, reveal an intimate coupling between the crystal structure and valence electron count. An increase in the valence electron count through P substitution results in breaking the interslab T-T dimers (d(T-T) = 3.74 A; T is a mixture of Si and P) and shear movement of the ( proportional, variant)(2)[Gd(5)T(4)] slabs in Gd(5)Si(2.75)P(1.25). The Gd(5)Si(2.75)P(1.25) phase extends the existence of the orthorhombic Sm(5)Ge(4)-type structures to the valence electron count larger than 31 e(-)/formula unit. Tight-binding linear-muffin-tin-orbital calculations trace the origin of the T-T dimer cleavage in Gd(5)Si(2.75)P(1.25) to a larger population of antibonding states within the dimers.