black crystal(s); dark brown solid; preparation: from melted As and Se; uses: vacuum deposition [CER91] [STR93] [MER06]
Arsenicselenide is used as a chalcogenide glass for infrared optics, as it transmits light with wavelengths between 870 nm and 17.2 μm.
As and Se are encapsuled into a quartz tube in vacuum and the tube is put into a rocking furnace. The capsule is heated at the temperature slightly higher than the melting point and rocked to mix each component completely followed by slow cooling.
Arsenic tri-selenide takes amorphous or glassy material. Strong absorption bands are observed when As2O3 is incorporated into the source materials or As2O3 is formed during fabrication by oxidetion. As2O3 takes the cubic system, the monoclinic system, and the glassy state. The strong absorption bands are observed at 1050, 805, and 480 cm-1 for the cubic crystal system, at 1100, 805 cm-1 for the monoclinic crystal system and at 805 and 630 cm-1 for the glassy material. The absorptions in the transmittance spectrum T2 agree with either of these absorption bands.
Low toxicity by ingestion. Whenheated to decomposition it emits toxic vapors of As andSe.
