Archive | April, 2014

Chemistry (I)

24 Apr

Zinc sulfide is a white powder of composition ZnS.H²O. It is used as a paint pigment, for whitening rubber and for paper coating. The zinc sulfide phosphors which produce luminescence by exposure to light are made with zinc sulfide mixed with about 2% sodium chloride (NaCl) and 0,005% copper, manganese or other activator, and fired in a nonoxidizing atmosphere. The cubic Crystal structure of zinc sulfide changes to a stable hexagonal structure at 1020°C, but both have the phosphor properties.