Mercury thioarsenate glasses: a hybrid chain/ pyramidal network

Mohammad Kassem (1) , S. Khaoulani (1) , Arnaud Cuisset (1) , David Le Coq (2) , Pascal Masselin (1) , Eugène Bychkov (1)

1 LPCA - Laboratoire de Physico-Chimie de l'Atmosphère
2 ISCR - Institut des Sciences Chimiques de Rennes

Very little is known about mercury chalcogenide glasses. Using Raman spectroscopy and DFT modelling, we show that the (HgS)x(As2S3)1-x glasses, 0.0 ≤ x ≤ 0.5, form a hybrid Hg–S chain/As–S pyramidal network, highly unusual for metal chalcogenide glasses. This network is evidenced by Hg–S stretching modes at 300 and 370 cm-1 and an As–S spectral envelope centred at 340 cm-1. The decreasing glass transition temperature is consistent with a gradual substitution of more rigid corner-sharing CS-AsS3/2 pyramids by flexible (HgS2/2)n chain fragments. Nevertheless we cannot exclude completely the presence of a small fraction of HgS4/4 tetrahedral units. A non-monotonic change in electronic transport properties and metacinnabar ß-HgS traces detected using neutron diffraction in large x = 0.5 samples support the dual structural role of mercury

Domaines: Matériaux; Chimie théorique et/ou physique

Mohammad Kassem, S. Khaoulani, Arnaud Cuisset, David Le Coq, Pascal Masselin, et al.. Mercury thioarsenate glasses: a hybrid chain/ pyramidal network. RSC Advances, 2014, 4 (90), pp.49236. ⟨10.1039/c4ra07811j⟩. ⟨hal-01426903⟩