Chromic nitrate

Chromia—alumina catalysts are prepared by impregnating T-alumina shapes with a solution of chromic acid, ammonium dichromate, or chromic nitrate, followed by gentie calciaation. Ziac and copper chromites are prepared by coprecipitation and ignition, or by thermal decomposition of ziac or copper chromates, or organic amine complexes thereof. Many catalysts have spiael-like stmctures (239—242). 

Olated Cr(III) reagents were prepared according to Equation 2 by reacting CrtNOg) with a calculated equivalent of NaOH. Chromic nitrate was used Decause the freshly prepared solution affords the hexaaqua Cr(III) cations. 

Chromic chloride, molecular formula, properties, and uses, 6 563t Chromic chromate, molecular formula, properties, and uses, 6 56 It Chromic fluoborate, molecular formula, properties, and uses, 6 563t Chromic fluoride, molecular formula, properties, and uses, 6 563t Chromic hydroxy dichloride, molecular formula, properties, and uses, 6 563t Chromic nitrate, molecular formula, properties, and uses, 6 563t Chromic oxide... 

The simple hydrated ionic salt, chromic nitrate, has a spectrum quite distinct from the ionic salts of cobalt and manganese. The principal peak shows a splitting. This may be related to the very strong aflSnity which chromium displays toward its first coordination sphere of water. 

Hexammino-chromic Iodide, [Cr(NII3)G]I3, is also formed by the decomposition of the nitrate. A solution of hexammino-chromic nitrate is shaken with solid potassium iodide, the precipitate formed is washed with hydriodic acid, dissolved in cold water, and repreeipitated with dilute acid. It separates in yellow rhombic plates and is sparingly soluble in cold water. On warming with hydriodic acid iodo-pent-ammino-iodide is not produced.1... 

Triethylenediamino-chromic Nitrate, [Cr(en)3](N03)3, is prepared from the chloride by treating the aqueous solution with the calculated quantity of silver nitrate the precipitated silver chloride is removed by filtration, and, on the addition of alcohol to the filtrate, the nitrate separates and is then rccrystaliised from water. It crystallises in yellow transparent clusters, which become reddish in colour on warming, but on cooling regain their original colour. 

Aquo-pentammino-chromic Nitrate, [Cr(NH3)5H20](N03)3, may be formed by a method similar to that for the bromide, or it may be produced by treating cliloro-pentammino-ehromie chloride in aqueous solution with 1-4 nitric acid and allowing the mixture to stand at 0° C. The solution is filtered and treated with a further portion of nitric acid and allowed to stand at 0° C., when the aquo-salt crystallises out.2 It is a yellowish-red crystalline salt, easily soluble in water, and decomposes if heated to 100° C. 

Diaquo-tetrammino-chromic Acid Nitrate, [Cr(NH3)4(H20)2] (N03)4.H, is formed when hydroxo-aquo-tetrammino-chromic di-thionate, [Cr(NH3)4(H20)(H0)]S206, is treated with fuming nitric acid. It forms light orange-coloured prismatic needles, which decompose in a desiccator over sodium hydroxide, or, on heating, being transformed into red nitrato-aquo-tetrammino-chromic nitrate, [Cr(NH3)4H20(N03)] (NOs).>... 

Nitro-pentammino-chromic Nitrate, [Cr(NI-I3)5NO2](N03)2, is obtained from the chloride by precipitation of a solution of the chloride with concentrated aqueous ammonium nitrate, or by decomposing a solution of aquo-pentammino-salt with half its volume of dilute nitric acid and addition of sodium nitrite. It crystallises in yellow octahedra, is less soluble in water than the corresponding chloride, and decomposes explosively on heating. 

Nitrato-pentammino-chromic Nitrate, [Cr(NH3)5N03](N03)2, is obtained from thiocyanato-pentammino-chromic nitrate, [Cr(NITs)s (SCN)](N03)2, by treating it with well-cooled fuming nitric acid until it has dissolved to a clear brownish-red liquid ice is then added slowly to the solution until the volume is double, when the nitrato-salt is precipitated as a fine, powdery, pale pink solid. It is sparingly soluble in water, and the solution is very easily decomposed. If warmed with... 

Chloro-pentammino-chromic Nitrate, [Cr(NH3)5Cl](NOs)2, is precipitated by the addition of excess of nitric acid at 0° C. to a solution of the chloride. It may be crystallised from water acidified with nitric acid, and obtained in red octahedral crystals which are more soluble in water than the chloride. The chloro-pentammino-salts react in aqueous solution with chloroplatinic acid, with precipitation of the very sparingly soluble chloroplatinate, [Cr(NH3)6Cl](PtCl6), which crystallises in yellow prisms. The oxalate, [Cr(NH3)5Cl]C204, and the ferrocyanide, [Cr(NH3)6Cl]2[Fe(CN)6].4H20, are precipitated by the... 

Chloro-aquo-tetrammino-chromic Nitrate, [Cr(NH3)(H20)Cl] (N03)2, is formed when the chloride is mixed with nitric acid, filtered and allowed to stand. It separates in purple rhombic crystals. 

EXERCISE 71. HEXAMMINO-CHROMIC NITRATE, [Cr(NH3)3] (N03)3 CHLORO-PENTAMMINO-CHROMIC CHLORIDE, [Cr(NH3)3Cl]Cl2... 

To the united filtrate add concentrated nitric acid, precipitating the hexammino salt (formerly called luteo-chromic nitrate). Filter off this salt, dissolve it in a little warm water to which a few drops of nitric acid has been added, and again precipitate the crystalline hexammino-chromic nitrate by the addition of nitric acid and by cooling. The yield is about 7 g. 

Chromic Nitrate, Cr(N03)3.9H20, obtained by w arming nitric acid with excess of chromic hydroxide (this giving a basic salt) and crystallising after the addition of a sufficient excess of nitric acid, forms purple rhombic prisms, melting at 36-5° C. and soluble in alcohol. The salt decomposes at 100° C. ... 

Mixed gels of hydrous ferric and chromic oxides were prepared by the addition of an equivalent amount of ammonium hydroxide to mixtures of the solutions of ferric nitrate (0.5M with respect to Fe20j) and chromic nitrate (0.5M with respect to Cr203). The dual gels were washed free of nitrate ions and air- or oven-dried. A series of mixtures corresponding to 20, 40, 60, and 80% Fe203 was prepared. 

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