Title: Arsenic Sulfide
CAS Registry Number: 12279-90-2
CAS Name: 2,4,6,8-Tetrathia-1,3,5,7-tetraarsatricyclo[3.3.0.03,7]octane
Additional Names: red arsenic sulfide; realgar; red orpiment; ruby arsenic; red arsenic glass; tetraarsenic tetrasulfide; C.I. Pigment Yellow 39; C.I. 77085
Molecular Formula: As4S4
Molecular Weight: 427.95
Percent Composition: As 70.03%, S 29.97%
Literature References: Prepn: Gmelins, Arsenic (8th ed.) 17, pp 417-422 (1952); Schenk in Handbook of Preparative Inorganic Chemistry vol 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 603.
Properties: Deep red, lustrous monoclinic crystals. mp 320°; bp 565°; d 3.5. Ignites at high temp. Practically insol in water; sol in alkali hydroxides; decomposed by HNO3; very slightly sol in hot CS2 and benzene.
Melting point: mp 320°
Boiling point: bp 565°
Density: d 3.5
Use: As pigment in painting; in fireworks as blue fire and to give an intense white flame; manuf shot; calico printing and dyeing; tanning and depilating hides.