Chromous hydroxide

Chrom-hydrat, -hydroxyd, n. chromic hydroxide, chromium(lll) hydroxide, -hydroxydul, n. chromous hydroxide, chromium(II) hydroxide. 

Cbronioxydul-. chromous, chromium(II). -hy-drat, n. chromous hydroxide, chroinium(II) hydroxide. 8alz, n. chromous salt, chro-nuum(n) salt. verbiudung, /. chromous compound, chroinium(II) compound. 

When an air-free solution of caustic potash is added to a solution of chromous chloride in absence of air, a brownish-yellow precipitate of chromous hydroxide, Cr(OH)2, is obtained which may be dried over sulphuric acid. On heating in the presence of an inert gas this does not yield chromous oxide, since it decomposes according to the equation ... 

Equation (32) represents reduction by O2+. There are, of course, many examples of reduction by Cr2+. Some, more closely related to the present problem, are given by Traube and also by other workers (73-76). In particular, Traube and Passarge (73) reported years ago that cinnamic and maleic acids were reduced at 100° by an aqueous suspension of an ill-defined chromous hydroxide. This reduction probably proceeds by a mechanism related to Eq. (32). 

The submitters used prepurified nitrogen, obtained from Matheson Company, Inc., East Rutherford, New Jersey, without further purification. The checkers passed Linde (H. P. Dry) nitrogen successively through chromous chloride solution, solid potassium hydroxide, Ascarite, and solid phosphorus pentoxide. 

The highest oxide of chromiunTi, chromic oxide, is acidic, and forms chromates and dichromates. The lowest oxide, CrO, is basic, forming the chromous ion Cr" and its salts. Chromic hydroxide, Cr(OH)g, representing the intermediate oxidation state, is amphoteric. With acids it forms the salts of chromic ion, such as chromic sulfate. Cr2(S04)3 and with strong base it dissolves to form the chromite ion, Cr(OH)4. ... 

Oxidation states of chromium - -2, - -3, and -f-6. Oi es of chromium chronate, FeCr204, and crocoite, PbCr04. Chromium metal and its alloys ferrochrome, alloy steels, stainless steel. The aluminothermic process (Goldschrtiidt process). Electrolytic chromium. Chromium trioxide, chromic acid, dichromic acid, potassium chromate, potassium didiromate, sodium chromate, lead chromate. Equilibrium between chromate ion and dichromate ion. Chrome-tanned leather. Chromic oxide (chrome green) chromic ion, chrome alum, chromic chloride, chromic hydroxide, chromite ion. Chromous compounds. Peroxy-chromic acid. 

The chromous salts, derived from the oxide CrO, arc analogous to the salts of divalent vanadium, manganese, and iron. This is seen in the isomorphism of the sulphates of the type R" SOj-THgO. The stability of such salts increases in the order of the atomic number of the metal. The chief basic oxide of chromium is the sesquioxidc CraO, which is closely allied to ferric oxide, and, like the latter, resembles aluminium oxide. The hydroxide, Cr(OH)3, with bases yields chromites analogous to, but less stable than, the aluminates. Chromic sulphate enters into the formation of alums. The chromic salts are very stable, but in the trivaJent condition the metal shows a marked tendency to form complex ions, both anions and cations thus it resembles iron in producing complex cyanides, whilst it also yields compounds similar to the cobaltamines. 

With alkali hydroxide a solution of chromous chloride yields a yellowish-brown precipitate which absorbs oxygen, forming a hydrated chromo-chromic oxide, Cr304.H20. 

Chromous acid (chromium(III) oxide hydroxide) CrOOH FDS 55... 

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