Arsenic

1. Arsenic Albertus Magnus (1193-1280), a German philosopher and theologian, was the first to state that arsenic has a metal-like nature. In De Mineralibus he described how the metal could be obtained by heating orpiment (As2S3) with soap. -Prolonged arsenic exposure causes skin and lung cancer and may cause other internal cancers as well. -Skin lesions, peripheral neuropathy, and anemia are hallmarks of chronic arsenic exposure. Isotope Half Life As-71 2.7 days As-72 26.0 hours As-73 80.3 days As-74 17.8 days As-75 Stable As-76 26.3 hours As-77 39.0 hours As-79 9.0 minutes Properties: Arsenic has a valence of -3, 0, +3, or +5. The elemental solid primarily occurs in two modifications, though other allotropes are reported. Yellow arsenic has a specific gravity of 1.97, while gray or metallic arsenic has a specific gravity of 5.73. Gray arsenic is the usual stable form, with a melting point of 817°C (28 atm) and sublimation point at 613°C. Gray arsenic is a very brittle semi-metallic solid. It is steel-gray in color, crystalline, tarnishes readily in air, and is rapidly oxidized to arsenous oxide (As2O3) upon heating (arsenous oxide exudes the odor of garlic). Arsenic and its compounds are poisonous. Element Classification: Semimetallic Density (g/cc): 5.73 (gray arsenic) Melting Point: 1090 K at 35.8 atmospheres (triple point of arsenic). At normal pressure, arsenic has no melting point. Under normal pressure, solid arsenic sublimes into a gas at 887 Date of Discovery: Known to the ancients Discoverer: Unknown Name Origin: From the Greek word arsenikos and the Latin word arsenicum Uses: Poison, conducts electricity, semiconductors Obtained From: mispickel