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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![PROTOXIDE OF COBALT. 12d § 109.] been rendered alkaline by ammonia, a solution of sulpbocarbonate of been remieieci i . ^ i^j is obtained, winch is barely tCSent :J7ve^^^^-^o.t blacAy reflected light. If the solution tianslucent, ana addition of the reagent will produce a teSSf;^l A' D. Braun). . The production of this colour xn i,,-«;.i-,r rlflntft solutions is characteristic ot nicJcel. ^'^ ll clllon^e of baryta, on digestion in the cold, does no precipitate nickel from solutions of its salts, unless sulphuric acid i^ ^'^Tf Nitrite of potassa with acetic acid does not throw down the nickel' even from concentrated solutions. In the presence of lime MxS, or strontia, however, a yellow crystalline nitrite of protoxide of nS and the alkaline earth is precipitated if the solution is not too. dnute The precipitate is sparingly soluble m cold water or dilute acetic acid, more xeadily in hot water to a green solution (Kunzel, 0. L. Erdmann). , i r 4- -j^ 15 Borax and microeosmic salt dissolve compounds of protoxide of nickel in the outer flame to clear beads. The borax bead is violet while hot, reddish-brown when cold; the microeosmic bead is reddish or brownish-red while hot, yeUow or reddish-yellow ^^l^e^i cold. In the inner flame, the microeosmic bead remains unaltered, but the borax bead becomes gray and cloudy from reduced metal. On continued beating the particles of nickel coUect together without fusing, and the bead loses its colour. t j. 16 By the reduction in the stick of charcoal, according to p. 24, the compounds of nickel yield after trituration white, shunng ductile spangles, which wiU be deposited on the point of a magnetic knife in the form of a brush. With nitric acid, they give a green solution, which can be further examined. § 109. d. Cobaltous Oxide or Protoxide of Cobalt, OoO [CoO]. 1. Metallic cobalt in the fused state is steel-gray, pretty hard, maUeable, difiicultly fusible, and magnetic; susceptible of poUsh; it does not oxidize in the air at the common temperature, but it oxidizes at a red heat; with acids it behaves Hke nickel. The solutions contain protoxide of cobalt. 2. Protoxide of cobalt is light brown, its hydrate a pale red powder. Both dissolve readily in hydrochloric, nitric, and sulphuric acids. Sesquioxide of cobalt, Co,03 [CoAl, is black; it dissolves m hydrochloric acid to protochloride, with evolution of chlorine. 3. The salts of protoxide of cobalt containing water of crystal- lization are red, the anhydrous salts mostly blue. The moderately con- centrated solutions appear of a light red colour, which they retain even though considerably diluted. The soluble neutral salts redden litmus slightly, and are decomposed at a red heat; sulphate of protoxide of cobalt alone can bear a moderate red heat without suffering decomposi- tion. When a solution of chloride of cobalt is evaporated, the pale red * Prepared by taking a solution of hydrate of potassa containing about 5 per cent., saturating one-half with sulphuretted hydrogen, adding the other half and then of volume of bisulphide of carbon, digesting at a gentle heat, and finally separating the dark orange-red solution from the undissolved bisulphide of carbon. The solution must be kept in a well-closed bottle.](https://iiif.wellcomecollection.org/image/b21966953_0149.jp2/full/800%2C/0/default.jpg)
