Au with sp3 Hybridization in Li5AuP2

J Phys Chem Lett. 2022 Jan 13;13(1):236-242. doi: 10.1021/acs.jpclett.1c03609. Epub 2021 Dec 30.

Abstract

The achievement of new bonding patterns of atoms in compounds is of great importance, which usually induces interesting physical and chemical properties. Rich oxidation states, diverse bonding types, and unique aurophilic attraction endow gold (Au) as a distinctive element. Here we report that a pressure-induced Li5AuP2, identified by a swarm intelligence-based structural prediction, becomes the first example of Au with sp3 hybridization. The most remarkable feature of Li5AuP2 is that it contains various frameworks made by AuP4, AuLi4, LiP4, and blende-like Li-P units, exhibiting noncentrosymmetry. The charge transfer from Li to Au makes Au 6p orbitals activate and hybridize with the 6s one. On the other hand, Li donating electrons to P and polar Au-P covalence make the constituent atoms satisfy the octet rule, rendering Li5AuP2 with a semiconducting character and a large second-order nonlinear optical response in the near-infrared region. Our work represents a significant step toward extending the understanding of gold chemistry.