Arsenic is a trivalent and pentavalent, solid, poisonous common element usually found combined with metals as arsenides, the commonest of which is arsenical pyrites, FeAsS. It has a steel colour and high metallic lustre, and tarnishes on exposure to the air, first changing to yellow, and finally to black. In hardness it equals copper; it is extremely brittle, and very volatile, beginning to sublime before it melts. It burns with a blue flame, and emits a smell of garlic. Its specific gravity is 5.76. It forms compounds with most of the metals. Combined with sulphur it forms or-piment and realgar, which are the yellow and red sulphides of arsenic. Orpiment is the true arsenicum of the ancients. With oxygen arsenic forms two compounds, the more important of which is arsenious oxides or arsenic trioxide (As40e), which is the white arsenic, or simply arsenic of the shops. It is usually seen in white, glassy, translucent masses, and is obtained by sublimation from several ores containing arsenic in combination with metals, particularly from arsenical pyrites.
Of all substances arsenic is that which has most frequently occasioned death by poisoning, both by accident and design. The best remedies against the effects of arsenic on the stomach are ferric hydroxide or magnesic hydroxide, or a mixture of both, with copious draughts of bland liquids of a mucilaginous consistence, which serve to procure its complete ejection from the stomach. Oils and fats generally, milk, albumen, wheat-flour, oatmeal, sugar or syrup, have all proved useful in counteracting its effect. Like many other virulent poisons it is a safe and useful medicine, especially in skin diseases, when judiciously employed. It is used as a flux for glass, and also for forming pigments. The arsenite of copper (Scheele's green) and a double arsenite and acetate of copper (emerald green) were formerly largely used to colour paper-hangings for rooms, but as poisonous gases are liable to be given off, the practice was abandoned. Arsenic compounds have in the past been used for colouring confectionery, and other articles, bright green. It is found in crude oil of vitriol, and occasionally in the past in products such as grape-sugar, beer, etc, in the manufacture of which oil of vitriol was employed. Arsenic tablets were formerly worn as protection against the plague. Research Arsenic
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Rocks & Minerals
Research Arsenic