Chromium alums

Gamer and Jennings [431] studied nucleation during the dehydration of potassium and ammonium chromium alums. Detailed kinetic measurements were made for the relatively enhanced rate of nucleation which followed admission of water vapour to the solid after a period of vacuum nucleation. This catalytic effect of water vapour is ascribed to its participation in the reorganization of the lattice which had collapsed during previous treatment in vacuum. 

N3Hs)A1(S04)3.12H30, Hydrazine alum. (N3H5)Cr(S04)3.12H30, Hydrazine chromium alum. 

Biiltemann 2 observed that vanadium ammonium alum separates out in blue crystals from a solution containing sulphuric acid, but from solutions containing a weak acid, or from neutral solutions, red crystals are obtained. (The chromium alums can also be prepared in differently coloured modifications.) The analytical data, melting-point, electrical conductivity, rate of efflorescence, and general behaviour of both kinds of crystals are identical, so that it is difficult to ascribe different constitutions to them. Meyer and Markowitz3 have shown that both forms separate out when the molecular proportion of sulphuric acid in the solution is less than that theoretically required, and attribute the red colour to the presence of traces of vanadous oxide, V203, or its hydroxide, V(OH)3. Vanadium rubidium and vanadium ciesium alums behave in the same way. A vanadium guanidine alum has also been prepared.4... 

The Cr1 ion readily forms complexes it exists in aqueous solution as CrfH 0)j. and forms other complexes wilh anions, such asCr(H 0).CI , Crother properties due to variation in the bonding. Compounds or the trichloride have been reported with the following arrangements CrtHjOlsClj. [CrfHiOlsCljCIi- HiO. and [Cr(HiO)4Cf CU2 H 0 Trivalenl chromium also forms double salts, notably the chromium alums, hydrated double salts of Cr(III) sulfate and the alkali metal (or thallium or ammonium) sulfates. 

Two solutions are prepared (a) 5 g. (0.01 mol) of potassium chromium alum is dissolved in 20 ml. of water and (b) 21 g. of sodium hydroxide (0.50 mol) and 10 g. of bigua-nide sulfate 2-hydratet is dissolved in 50 ml. of water. Solution b is heated to 75°, and solution a is added drop by drop with constant stirring. As each drop strikes the alkaline solution, there is a momentary formation of green chromium hydroxide which dissolves to form a dark red solution. As the reaction progresses, bright red, prismatic crystals separate from the solution. After all of solution a has been added, the mixture is cooled in ice water until no more solid separates. The crystals are filtered on a fritted-glass funnel and washed with 5 ml. of cold water. 

Salmonella typhimurium TA100, TA1535 TA98, TA1537, TA1538 Reverse mutations Base pair substitutions Frame shift mutations - - De Flora 1981 Petrilli and De Flora 1978b Chromium trichloride hexahydrate, chromium nitrite, monohydrate, chromium potassium sulfate, chromium acetate, neochromium, chromium alum, chromite... 

SYNS CHROME ALUM CHROME POTASH ALUM CHROMIC POTASSIUM SULFATE CHROMIC POTASSIUM SULPHATE CHROMIUM POTASSIUM SULFATE (1 1 2) CHROMIUM POTASSIUM SULPHATE CRYSTAL CHROME ALUM POTASSIUM CHROMIC SULPHATE POTASSIUM CHROMIUM ALUM POTASSIUM DISULPHATOCHROMATE(III) SULFURIC ACID, CHROMIUM (3+) POTASSIUM SALT (2 1 1)... 

Potassium Chromium Alum, Chrome Alum, KjSOj. Cr2(S04)3.24H20, first isolated by Mussin-Pusehin, is obtained by the reduction of a mixture of potassium dichromate and sulphuric acid by sulphurous acid, alcohol, oxalic acid, etc. ... 

Chromium alum is soluble in water, 100 c.c. of water at 25° C. dissolving 24-39 grams of the hydrated salt. The violet sohrtion, on heating at 50° to 70° C., becomes green, and is then crystallisable with difficulty. The violet solution, even at ordinary temperatures, slowly... 

Crystalline rubidium chromium alum has been described. ... 

Ammonium Chromium Alum, (NH4)2S04.Cr2(S04)3.24H20, crystallises from a suitable mixture of solutions of its component salts in efflorescent octahedra of density 1-73, melting at 100° C. with loss of ISHjO. 

Ammonium chromium alum is soluble in water to the extent, at 25° C., of 21-21 grams of the hydrated salt in 100 c.c. of water, yielding a bluish- iolet solution which becomes green at 70° to 80° C. A study of the equilibria existing in such a solution makes it appear that the change from the violet to the green modification d.oes not take place at all at 0° C., but that at 40° C. the solution contains about 40 per cent, of the green alum. ... 

Hydroxylamine Chromium Alum, (NH20H)2H2S04.Cr2(S04)3. 24HaO, is stated to exist. 

Hydrazine Chromium Alum, (N2H4)2H2S04.Cr2(S04)3.24H20,... 

If there is no available salt of constant composition, such as copper(II) sulphate or iron(III), aluminium or chromium alums, it is advisable to prepare first a stock solution of an approximate concentration, slightly higher than required and to determine the concentration by a gravimetric or volumetric method. After suitable calculations the solution is diluted with pure solvent to obtain a solution containing exactly, e.g., 1 mg/ml of the given element. In some cases, standard solutions are obtained by dissolving a precisely weighed amount of the element in its pure form. 

Basicity chrome alum CCRIS 7532 Chrome alum Chrome potash alum Chromic potassium sulfate Chromic potassium sulphate Chromium potassium bis(sulphate) Chromium potassium sulfate (1 1 2) Chromium potassium sulfate (CrK(S04)2) Chromium potassium sulphate Chromium(lll) potassium sulfate Crystal Chrome Alum EINECS 233401-6 Potassium chromic sulfate Potassium chromic sulphate Potassium chromium alum Potassium chromium disulfate (KCr(S04)2) Potassium disulphatochromate (III) Sulfuric acid, chromium(3 ) potassium salt (2 1 1). Mordant for dyeing fabrics uniformly [dodecahydratej mp = 89° d = 1.83 soluble in 4 parts H2O. 

Materials Potassium aluminium alum, potassium chromium alum. 

Directions (a) Dissolve 16 grams of potassium aluminium alum in 100 c.c. of hot water, filter if necessary, and cool the solution to room temperature in running water. Shake occasionally for five minutes 8 grams of finely powdered potassium chromium alum with 100 c.c. of water at about 30°. The temperature should not be allowed to go higher than 35° in order to prevent the change of the chromium salt to the green modification. Filter the solution. In four beakers place the following (1) 40 c.c. of the solution of aluminium alum and 10 c.c. of the chromium alum, (2) 20 c.c. of the former and 10 c.c. of the latter, (3) the rest of the solution of the former and (4) the rest of the solution of the latter. 

Solubility of Caesium Chromium Alum, Caesium Iron Alum, Caesium Indium Alum, and of Caesium Vanadium Alum in Water. 

Potassium Chromium Alum KjCrj(SOJ. 24HjO 12.51 24.39 o o44i Tellurium Chromium Alum TejCr2(SO ). 24HjO 10.41 16.38 0.021a... 

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