Volume 1

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

  • Fownes, George, 1815-1849.
Date:
1877
Catalogue details

Licence: Public Domain Mark

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

    544/586 (page 526)
    potasli in the same manner as that of the dichloride, neither does yield any blue precipitate on boiling. The only definite oxygen-salts of iridium that have been obtained are double salts containing sulphurous and dithionic acids. Hypo-iridoso-potassic Sulphite, IrSOg.SKgSOg, is obtained as a white crystalline powder, when the mother-liquor obtained in pre- paring potassium chloriridite by passing sulphurous oxide through a solution of the chloriiidate, is evaporated to a small bulk. Siilphides.—Three sulphides of iridium are known, analogous to the first thi-ee oxides above described. The sesquisidpliide and disulpMde are obtained as brown-black precipitates by treating the solutions of the trichloride and tetrachloride respectively vdth. hydrogen sulphide. The monosulphide is a greyish-black substance obtained by decomposing either of the higher sulphides in a close vessel. Ammoniacal Compounds of Iridium.—The chlorides of iridos- ammowMmandmdosodmmmonMm,Ir(NH3Cl)2andIr[NH2(NH4)Cl]2, together with the corresponding sulphates, are prepared like the platinous compounds of analogous composition, which they also re- semble in their properties. The nitmtochloride, Ii^^jJg^^jq'g^^Q]^'' is formed by heating the chloride, Ir (NH3C1)2, with strong nitric acid. Iridiodiammonium chloride, Cl2lr[NH2(NH^)Cl]2, is obtained as a violet precipitate by treating the nitrate just mentioned with hydrochloric acid.* The compound, lONHj.IrjCL, analogous to the rhodium-compound above described (p. 522), but having no analogue in the platinmn series, is obtained as a flesh-coloured crystalline powder by pro- longed digestion of ammonium chloriridiate with warm aqueous ammonia. The corresponding carbonate, nitrate, and sulphate have also been prepared, t Iridic solutions (containing the dioxide or tetrachloride) are of a dark brown-red colom'; ii-idious solutions (containing the sesqui- oxide or trichloride) have an olive-green colour. The characters of an iridic solution are best observed with sodiimi chloriridiate, all the other iridic compounds being but slightly soluble. Iridic solutions give with ammonium or piotassium chloride a crys- talline precipitate of ammonium or potassium chloriridiate, which is distinguished fi'om the corresponding platinum precipitate by its dark brown-red colour, and further by its reduction to soluble clilor- iridite when treated with solution of hydi'ogen sulpiride. This re- action serves for the separation of iridium from platinum. * S Ic o b 1 i k 0 f f, Anu. Ch. Pbarm. Ixxxiv. 275. •)• Claus, Beitriigezur Chemie der Platinvietalle. Dorpat, 1854.