Volume 1

Fownes' manual of chemistry : theoretical and practical / [George Fownes].

  • George Fownes
Date:
1877
Catalogue details

Licence: Public Domain Mark

Credit: Fownes' manual of chemistry : theoretical and practical / [George Fownes]. Source: Wellcome Collection.

    515/586 (page 497)
    Nickel Oxides and Oxysalts.—Nickel forms two oxides analo- gous to the two principal oxides of iron. The monoxide, NiO, is prepared by heating the nitrate to redness, or by precipitating a soluble nickel salt with caustic potash, and washing, cbying, and igniting the apple-green hydrated oxide thrown down. It is an ashy-grey powder, freely soluble in acids, which it completely neutralises, forming salts isomorphous with those of magnesium and the other members of the same group. Nickel salts, when hydrated, have usually a beautiful emerald-green coloiu'; in the aidiycli-ous state they are yellow. The sesquioxide, iSIiaOg, is a black insoluble substance, prepared by passing chlorine through the hydrated monoxide suspended in water ; nickel chloride is then formed, and the oxygen of the oxide decomposed is transferred to a second portion. It is also produced when a salt of nickel is mixed with a solution of bleaching-powder. The sesquioxide is decomposed by heat, and evolves chlorine when treated with hot hydrochloric acid. Nickel Sulphate, NiSO^.VHgO.—This is the most important of the nickel salts. It forms green prismatic crystals, which require 3 parts of cold water for solution. Crystals with six molecules of water have also been obtained. It forms with the sulphates of potassiiim and ammonium beaiitiful double salts, ]SriK2(S04)2.6H20, and Ni(NH^)2(S04)2.6H20, isomorphous with the corresponding magnesium salts. _ When a strong solution of oxalic acid is mixed with sulphate of nickel, a pale bluish-green precipitate of oxalate falls after some time, very little nickel remaining in solution. The oxalate can thus be obtained for preparing the metal. Nickel Carbonate, NiCOg.—When solutions of nickel sulphate or chloride and of sodium carbonate are mixed, a pale-green precipi- tate falls, which is a combination of nickel carbonate and hydrate. It is readily decomposed by heat. Pure nickel-salts are conveniently prepared on the small scale from crude speiss or kupfernickel by the following process :—The mineral is broken into small fragments, mixed with from one-fourth to half Its weight of iron filings, and the whole dissolved in nitro- muriatic acid. The solution is gently evaporated to dryness, the residue treated with boiling water, and the insoluble iron arsenate removed by a filter. The liquid is then acidulated with hycbochloric acid, treated with hydrogen sulphide in excess, which precipitates the copper, and, after filtration, boiled with a little nitric acid to brmg back the iron to the state of sesquioxide. To the cold and largely diluted lir^uid solution, acid sodium carbonate is gradually added by which the ferric oxide may be completely separated without loss ot nickel-salt. Lastly, the filtered solution, boiled with sodium carbonate m excess, yields an abundant pale green precipitate of nickel carbonate, from which all the other compounds may be pre- F0WNE3.—VOL. I. 2 I