Germanium monosulfide or Germanium(II) sulfide is the chemical compound with the formula GeS. Germanium sulfide is a red-brown powder or black crystals. It hydrolyzes slowly in moist air but rapidly reacts in water forming Ge(OH)2 and then GeO.E. G. Rochow, E. W. Abel ,1973, The Chemistry of Germanium Tin and Lead, Pergamon Press, It is one of a few sulfides that can be sublimed under vacuum without decomposition.Michael Binnewies, Robert Glaum, Marcus Schmidt, Peer Schmidt, 2012, Chemical Vapor Transport Reactions, De Gruyter, It also forms chalcogenide glasses and is a semiconductor.
Preparation First made by Winkler by reducing GeS2 with Ge. Other methods include reduction in a stream of H2 gas, or with an excess of H3PO2 followed by vacuum sublimation.
Structure It has a layer structure similar to that of black phosphorus. The Ge-S distances range from 247 to 300 pm. Molecular GeS in the gas phase has a Ge-S bond length of 201.21 pm.
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