Gold(i) sulfide: Unusual bonding and an unexpected computational challenge in a simple solid
We report the experimental high-pressure crystal structure and equation of state of gold(I) sulfide (Au2S) determined using diamond-anvil cell synchrotron X-ray diffraction. Our data shows that Au2S has a simple cubic structure with six atoms in the unit cell (four Au in linear, and two S in tetrahedral, coordination), no internal degrees of freedom, and relatively low bulk modulus. Despite its structural simplicity, Au2S displays very unusual chemical bonding. The very similar and relatively high electronegativities of Au and S rule out any significant metallic or ionic character. Using a simple valence bond (Lewis) model, we argue that the Au2S crystal possesses two different types of cov…
Gold(i) sulfide: unusual bonding and an unexpected computational challenge in a simple solid† †Electronic supplementary information (ESI) available: Analysis of the pressure-induced amorphization in Au2S and calculated band structure. See DOI: 10.1039/c9sc00371a
Cubic cuprite-type gold(i) sulfide presents unique chemical bonding, which makes it unmodelable using current DFT methods, and a computational challenge.