Compression of Silver Sulfide: X-ray Diffraction Measurements and Total-Energy Calculations

[EN] Angle-dispersive X-ray diffraction measurements have been performed in acanthite, Ag2S, up to 18 GPa in order to investigate its high-pressure structural behavior. They have been complemented by ab initio electronic structure calculations. From our experimental data, we have determined that two different high-pressure phase transitions take place at 5 and 10.5 GPa. The first pressure-induced transition is from the initial anti-PbCl2-like monoclinic structure (space group P2(1)/n) to an orthorhombic Ag2Se-type structure (space group P2(1)2(1)2(1)). The compressibility of the lattice parameters and the equation of state of both phases have been determined. A second phase transition to a P2(1)/n phase has been found, which is a slight modification of the low-pressure structure (Co2Si-related structure). The initial monoclinic phase was fully recovered after decompression. Density functional and, in particular, GGA+U calculations present an overall good agreement with the experimental results in terms of the high-pressure sequence, cell parameters, and their evolution with pressureFinancial support from the Spanish Consolider Ingenio 2010 Program (Project No. CDS2007-00045) is acknowledged. The work was also supported by the Spanish MICCIN under Projects No. CTQ2009-14596-C02-01/02 and MAT2010-21270-C04-01, as well as from Comunidad de Madrid and European Social Fund: S2009/PPQ-1551 4161893 (QUI-MAPRES). The Diamond Light Source is also acknowledged for provision of beamtime. O.G. acknowledges financial support from the Vicerrectorado de Investigacion y Desarrollo de la UPV (Grants PAID-06-11 and PAID-05-11 through projects UPV2012-1469 and UPV2012-2682, respectively). M.M. is also grateful to the Principado de Asturias and FICYT for a Clarin postdoctoral fellowship (POST 10-54).Gomis Hilario, O.; Santamaria Pérez, D.; Chuliá-Jordaán, R.; Marqués, M.; Menendez, JM.; Ruiz-Fuertes, J.; Sans, JA.... (2012). Compression of Silver Sulfide: X-ray Diffraction Measurements and Total-Energy Calculations. Inorganic Chemistry. 51:5289-5298. https://doi.org/10.1021/ic300236pS528952985