Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![OXIDE OF GALLIUM. f§ easily dispersed by the blowpipe flame, indium dissolves ^n dlteTdrn' chloric or sulphuric acid with evolution of hydrogen sTow^in the c^^^^^^^ more rapidly on heating; with cold concentrated su phS add it 1^ d£''i^-;'°^'°-r^ ^''T'' ^^^'^^^^'^ anh^Sr ulphate of n! oSTe 'in 0 nn r^'.'^^^^ ^^l'''^^'^ ease. The oxme, In^Uj [in OJ, is reddish-brown when hot, straw-coloured when rold • ll It I ^^'''^1 fl-es; when ignit'ed in hydrogen or with har-' Sined S -f ^''-^ '^^ ™^tallic globules are ODtamed. The ignited oxide dissolves slowly in acids in the cold b,i+ ;S and^hT'^?'^^'' ''^'.Y '^''^ ^^e -^Phate nitrate, and chloride are readily soluble in water. The chloride is volatile SZn^^T?*'' ^^^^W^?^*? of alumina; tartaric acid prevents the pfe- or^ odX Ji^ but dissolves in potassa or soda forming ahquid which soon becomes turbid. On boiling the solution or on adding chloride of ammonium, hydrated oxide of indSm separates' ^ gelatinous carWtef when h^T^lj ^ down, the precipitate dissolves in carbonate of ammonia but not m carbonate of potassa or carbonate of soda; if the soSn fn ™i ? ? ^^''?^^ a white bulky precipitate. Alkaline oxalates produce a crystalline precipitate. If acetate of soda is added to the near y neutral solution of the sulphate, and it is then boiled a basic .'oK''\^'P?l^'^-. digestion ^with carbonate o? ba^ytk in the ?Tht nffnvi? ' 'f''''^ '^^^^ of basic salt! iil !i J* separatmg indium from zinc, manganese, cobalt S theiIr^^^^ T^'-^ l^^'F^'T^'i^^ hydrogen throws down the whole f inn .1? T +V w7 ^^'^P}'^^ f Indium from a neutral or acetic acid solu- tion even when the latter is strongly acidified with acetic acid. If the solution is strongly acidified with a mineral acid and moderately concentrated, it is not precipitated but yellow sulphide of indium is thrown down if the solution IS very dilute. Sulphuretted hydrogen with alkahne solutions, and fwSw ^ ^' /'^^T'^'^.^'S solutions, yield a white precipitate (probab y hydrosulphide of mdium). If yellow sulphide of indium is boiled with yellow sulphide of ammonium, it also becomes white and partially dissolves On coolmg, sulphide of indium (?) separates as a white voluminous ■ precipitate. Perrocyanide of potassium produces a white precipitate ±errieyanide and sulphocyanate of potassium and dichromate of potassa produce no precipitate, but ehromate of potassa gives a yellow precipitate. Zinc precipitates the metal in the form of white shining Jaminae Indium compounds produce a peculiar bluish violet tinge in a colourless flame. The spectrum has two characteristic blue lines fsee the spectrum table). With the chloride, the lines, especially a, appear brightest,_ but they are very transient. For obtaining more persistent lines the sulphide, IS the most suitable compound. ' d. Oxide of Gallium. _ Hitherto gallium has been found only in some zinc blendes, and only in very minute quantity. It is a white metal, which, when fused, is silver- white; on solidifying it becomes crystalline, duller, and of a bluish white; it melts at 30-16°. Its sp. gr. is 6-956, it is hard, not very ductile, and remains- unaltered on exposure to the air at the ordinary temperature; it is only oxidized slightly when heated to redness, and does not volatilize at that temperature. Water, even when boiling, is not decomposed by gallium. Is^itric acid has hardly any action on gaUium in the cold, but on warming, it dissolves with evolution of red fumes. Hydrochloric acid, potassa, and ammonia readily dissolve galhum, hydrogen being given off. Gallium oxide,. CrajOg [Ga203], and its hydrate are white. On heating the oxide to redness in](https://iiif.wellcomecollection.org/image/b21966953_0160.jp2/full/800%2C/0/default.jpg)
