Analysis of electronic structures and chemical bonding of metal-rich compounds. I. Density functional study of Pt metal, LiPt2, LiPt, and Li2Pt.

First principles density functional theory calculations were carried out for the series of metal-rich compounds, LiPt₂, LiPt, and Li₂Pt, and elemental Pt for comparison, to probe the bonding picture that captures the essence of their electronic structures. Our analysis shows that the 5d-electron configuration of Pt in these compounds is close to (5d)¹⁰, and the electrons released from the Li atoms in the Li/Pt binary compounds are delocalized among the Pt⁰ atoms and Li⁺ ions through the interactions of the Pt 5d orbitals of each Pt with the Pt 6s/6p of neighboring Pt atoms and the Li 2s/2p orbitals of neighboring Li atoms. The electron counting schemes best representing the electronic structures of Pt metal, LiPt₂, LiPt and Li₂Pt are Pt⁰ (d¹⁰), Li⁺[Pt⁰ (d¹⁰)]₂(e^-), Li⁺[Pt⁰ (d¹⁰)](e^-), and (Li⁺)₂[Pt⁰ (d¹⁰)](2e^-), respectively, and hence the Pt atoms of the Li/Pt binary compounds are predicted to exist as partially negative anions. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008 [ABSTRACT FROM AUTHOR]