title: Gold as a 6p-Element in Dense Lithium Aurides.
abstract: The negative oxidation state of gold (Au) has drawn a great attention due to its unusual valence state that induces exotic properties in its compounds, including ferroelectricity and electronic polarization. Although monatomic anionic gold (Au(-)) has been reported, a higher negative oxidation state of Au has not been observed yet. Here we propose that high pressure becomes a controllable method for preparing high negative oxidation state of Au through its reaction with lithium. First-principles calculations in combination with swarm structural searches disclosed chemical reactions between Au and Li at high pressure, where stable Li-rich aurides with unexpected stoichiometries (e.g., Li4Au and Li5Au) emerge. These compounds exhibit intriguing structural features like Au-centered polyhedrons and a graphene-like Li sublattice, where each Au gains more than one electron donated by Li and acts as a 6p-element. The high negative oxidation state of Au has also been achieved through its reactions with other alkali metals (e.g., Cs) under pressures. Our work provides a useful strategy for achieving diverse Au anions.
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, China.|Faculty of Chemistry, Northeast Normal University , Changchun 130024, China.
authors.forename: Guochun
authors.initials: G
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, China.
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Peng
authors.affiliation: Departmento de Física de la Materia Condensada, Universidad del País Vasco , UPV/EHU, 48080 Bilbao, Spain.|Donostia International Physics Center (DIPC), 20018 Donostia, Spain.|Centro de Física de Materiales CFM, Centro Mixto CSIC-UPV/EHU, 20018 Donostia, Spain.
authors.forename: Aitor
authors.initials: A
authors.lastname: Bergara
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, China.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Ma