Arsenic, Elemental

CAS RN:7440-38-2

Other Properties

A yellow modification which has no metallic properties is obtained by sudden cooling of arsenic-vapor. This yellow arsenic is converted back to the gray modification upon very short exposure to ultraviolet light.
Vaporization becomes apparent at 100 deg C and is already rapid at 450 deg C; Brinell hardness: 147; Mohs' scale: 3.5; heat of sublimation: 30.5 kcal/g-atom; 7.63 kcal/g-atom; specific heat: 0.0822 for 0 deg C to 100 deg C; heat of fusion: 22.4 kcal/g-atom; 6.620 kcal/g-atom; not attacked by cold sulfuric acid or hydrochloric acid; converted by HNO3 or hot H2SO4 into arsenous or arsenic acid; dielectric constant: 10.23 @ 20 deg C and 60 cycles
Triple point: 817 deg C; sublimes at 614 deg C; specific gravity: 1.97 (yellow modification), 5.73 (gray or metallic modification)
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