GERMANIUM DISULFIDE

Germanium disulfide (GeS2) or germanium (IV) sulfide is a white high melting crystalline solid. It is a 3-dimensional polymer.¹ It can be obtained by the reaction between hydrogen sulfide and germanium tetrachloride in a concentrated hydrochloric acid solution. It is used as a semiconductor. It is also used in photo optic applications, e.g. in chalcogenide glasses for second harmonic generation^.2

1. https://en.wikipedia.org/wiki/Germanium_disulfide
2. M. Guignard, V. Nazabal, F. Smektala, J. L. Adam, O. Bohnke, C. Duverger, A. Moreac, H. Zeghlache, A. Kudlinski, G. Martinelli, Y. Quiquempois, Chalcogenide glasses based on germanium disulfide for second harmonic generation, Advanced Functional Materials, 2007, vol. 17, pp. 3284-3294

black crystal(s); can be prepared by reacting GeO2 and sulfur [KIR78] [STR93]