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Mixed‐valence Compounds: AuO 2 and AuS
Author(s) -
Tang Meng,
Zhang Yanmei,
Li Siya,
Wu Xi,
Jia Yan,
Yang Guochun
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800715
Subject(s) - valence (chemistry) , chemistry , octahedron , crystallography , band gap , chemical physics , condensed matter physics , crystal structure , physics , organic chemistry
Mixed‐valence compounds are of great interest due to their interesting properties and wide applications. Recently, gold (Au) chemistry has experienced an unprecedented development. However, Au with mixed‐valence states in Au−O compounds has not been reported thus far. Here, two hitherto unknown AuO 2 and AuS compounds with mixed‐valence character were identified with the aid of first‐principles swarm structure searching calculations. AuO 2 consists of quasi‐square AuO 4 moiety and AuO 6 octahedron in which Au shows the mixed‐valence states of III and V, the first example in Au−O binary compounds. AuS contains the linear AuS 2 and quasi‐square AuS 4 units exhibiting Au I/III mixed‐valence states. The analysis of electronic property demonstrates that AuO 2 and AuS are narrow band gap semiconductors with strong hybridization between Au 5d and O 2p or S 3p. With the increase of pressure, Au−O and Au−S compounds show completely different thermodynamic stabilities, resulting from distinct shifting of pressure‐induced atomic orbital energy levels of O and S atoms. Our work provides an opportunity for understanding mixed‐valence character in Au−O and Au−S compounds