: a slightly water-soluble crystalline poisonous compound HgO known in two forms (1) a yellow finely divided powder obtained usually by precipitation from solutions of mercury chloride (sense b) and sodium hydroxide and used chiefly in medicine (as in antiseptic ointments), in antifouling paints, and in making other mercury compounds (2) a bright red coarse powder obtained by precipitation from hot solutions or by heating mercurous nitrate and used similarly to the yellow form and also in dry cells — called also mercury(II) oxide
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Chem.
a slightly crystalline, water-soluble, poisonous compound, HgO, occurring as a coarse, orange-red powder (red mercuric oxide) or as a fine, orange-yellow powder (yellow mercuric oxide): used chiefly as a pigment in paints and as an antiseptic in pharmaceuticals.
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mercuric oxide,
a yellow or orange-red powder which dissolves in acids, but not in water, used in the manufacture of mercury salts, pigments, paints, and pottery, and also in ointments for the treatment of parasitic skin diseases and eye diseases. Formula: HgO
Useful english dictionary. 2012.