arsenious

[Eng. arseni (c); suff. -ous.] Pertaining to arsenic; having arsenic as one of its constituents. arsenious oxide, or arsenious anhydride, As2O3, called in the hydrated state arsenious acid . It is formed by burning arsenic in the air, but is obtained by roasting arsenical pyrites, ores of tin, cobalt, ., which contain arsenic, in a furnace supplied with air, and condensing it. Arsenious oxide crystallises in octohedra. It volatilises at 218° C. If it is condensed on a hot surface it fuses into a vitreous form, which is more soluble in water than the crystalline variety. One part di olves in twelve parts of hot and thirty parts of cold water; no definite hydrate exists. It is insoluble in alcohol and ether. Arsenious oxide is a violent irritant poison, two grains producing death, but by commencing with small doses it is po ible to take even four grains without injury. The Tyrolese eat arsenic to increase the power of the respiratory organs, as they have to climb mountains. Arsenious oxide is used in medicine in small doses in skin diseases. It is rapidly absorbed into the blood when it is applied to a wound. The best antidote is obtained by adding magnesia to ferric chloride; the mixture of sesquioxide of iron and magnesia can be used at once, without washing it. Arsenious oxide reduces chromic acid, manganic acid, .; but it is reduced to metallic arsenic by pota ium, charcoal, sulphur, and phosphorus at red heat. Arsenious oxide unites with bases forming arsenites , but they are not very stable compounds. Their solutions give a yellow precipitate with argentic nitrate, soluble in acetic acid, also in caustic potash; a light -green precipitate (Scheele's green) with cupric salts. Aceto -arsenite of and suff. -lite . Altered by Dana from the name arsenite , which is used in another sense in Chemistry.) A mineral, the same as White Arsenic, Oxide of Arsenic, and Arsenious Acid. It is isometric, occurs octahedral, usually in minute stelliform crystals, or crusts, investing other substances, or botryoidal or stalactitic. The hardne is 15, the sp. gr. 3.698, the lustre vitreous or silky, the colour white, occasionally tinged with yellowish or reddish, the taste somewhat sweet. Composition: Oxygen, 2424; arsenic, 75-76100. Occurs at Wheal Sparnan, in Cornwall, also on the Continent. Dana has an Arseno lite Group, containing this mineral and Senarmontite. It is the first placed under "Oxyds of elements of the Arsenic and Sulphur Groups, Series ii."