zinc oxide, chemical compound, ZnO, that is nearly insoluble in water but soluble in acids or alkalies. It occurs as white hexagonal crystals or a white powder commonly known as zinc white. Zinc white is used as a pigment in paints; less opaque than lithopone, it remains white when exposed to hydrogen sulfide or ultraviolet light. It is also used as a filler for rubber goods and in coatings for paper. Chinese white is a special grade of zinc white used in artists' pigments. Because it absorbs ultraviolet light, zinc oxide can be used in ointments, creams, and lotions to protect against sunburn. Crystalline zinc oxide exhibits the piezoelectric effect, is luminescent, and is light sensitive. Zinc oxide occurs in nature as the mineral zincite. Zinc peroxide, ZnO 2· 1⁄2 H 2O, is a white to yellow powder used in antiseptic ointments.
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