[EN] In this work we study the pressure behaviour of the orpiment (monoclinic) and anorpiment (triclinic) layered structures of As2S3 by means of ab initio calculations performed within the density functional theory, as part of an ongoing theoretical and experimental joint effort to provide a comprehensive picture of the bonding of this interesting material and the evolution of its structural, electronic, and vibrational properties under pressure.

The authors acknowledge the financial support from the Ministerio de Economia y Competitividad (MINECO) of Spain through Projects No. MAT2013-46649-C04-02-P and MAT2013-46649-C04-03-P. Computer time in the MALTA computer cluster at the University of Oviedo, Spain, is also gratefully acknowledged (MINECO Project No. CSD2007-00045).