Nomenclature
CAS number: 1344-48-5
Vermilion; Chinese red; C.I. Pigment Red 106; C.I. 77766.
HgS; mol wt 232.66.
Hg 86.22%, S 13.78%.
Description and 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
(α-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 FeSO
4 for marking linen; manuf fancy colored papers; as pigment.
Therapeutic Category
Antibacterial.
Keywords
Antiseptic/Disinfectant; Mercurial compounds