Title: Mercuric Sulfide, Red
CAS Registry Number: 1344-48-5
Additional Names: Vermilion; Chinese red; C.I. Pigment Red 106; C.I. 77766
Molecular Formula: HgS
Molecular Weight: 232.66
Percent Composition: Hg 86.22%, S 13.78%
Literature References: Occurs in nature as the mineral cinnabar. Prepd from mercuric acetate, ammonium thiocyanate, glacial acetic acid and hydrogen sulfide: Newell et al., Inorg. Synth. 1, 19 (1939). See also Colour Index vol. 4 (3rd ed., 1971) p 4682.
Properties: Bright scarlet-red powder, lumps, hexagonal crystals (a-form); blackens on exposure to light, particularly in presence of H2O or alkali hydroxides. At about 250° becomes brownish, at higher temp black, but red again on cooling. When ignited in air it dec into metal and sulfur, the latter burning to SO2. Practically insol in water; not attacked by HNO3 or cold HCl; dec by hot concd H2SO4; sol in aqua regia with separation of S, in warm hydriodic acid with evolution of H2S. Protect from light.
Use: For coloring plastics, sealing wax, and with FeSO4 for marking linen; manuf fancy colored papers; as pigment.
Keywords: Antiseptic/Disinfectant; Mercurial compounds.