Hexamminecobalt chloride

Hg(N03)2]iH20, 8.5 grams, plus 5 ml 6M nitric acid, is dissolved in water and made up to 500 ml. This solution must he standard-ized. (b) Potassium chloride, O.IN. Dry this salt at 110° for several hours and cool in a desiccator, and weigh out accurately the appropriate amount to prepare 250 or 500 ml of solution dissolve in water, transfer to the volumetric flask, make up to the mark, (c) Sodium nitroprusside, 10 per cent. This solution should be fresh that is, it should not be kept for more than a week, (d) Hexamminecobaltic chloride. Weigh out accurately about 0.9 gram of salt, dissolve in water, and make up to 100 ml in a volumetric flask. 

To standardize the mercuric nitrate, pipette 10 ml of O.lN potassium chloride into a 250-ml Erlenmeyer flask then add 40 ml of water (measured with a graduate) and 3 drops of 10 per cent sodium nitroprusside. Titrate with mercuric nitrate, shaking well between additions as the end point is neared. The end point is marked by a permanent white turbidity and is quite sharp. When the mercuric nitrate has been standardized, titrate the hexamminecobaltic chloride solution by the same procedure, taking care to have the volume of solution in the titration flask the same as in the standardization. The end point arrives somewhat early because of the reaction HgCh + Hg++—> 2HgCl+ but by performing the standardization and titration under similar conditions, with the final mercuric chloride concentrations almost the same, this error, which is small in any case, becomes quite negligible. 

The solubility of hexamminecobaltic chloride in water is 7.0 grams per 100 ml of solution at 20°, Calculate the solubility product and, neglecting activity coefficients, calculate the solubility in 2.0-molar hydrochloric acid. 

Hexamminecobalt(IH) chloride [10534-89-1] M 267.5. Crystd from warm water (8mL/g) by cooling. [Bjerrum and McReynolds Inorg Synth 2 217 1946.]... 

Sodium hexanitrocobaltate (III) Hexamminecobalt(III) chloride Carbonatotetramminecobalt(III) nitrate... 

Hexamminecobalt (II) chloride has a pale yellowish-pink color. A deeper yellow or brownish tint indicates that oxidation has taken place. 

Figure 2 shows the precipitation behavior of Py(IV) and U(VI) carbonato complex ions. The concentration of Pu(IV) ions in the supernatant decreases gradually to a minimum ( 20jjgPu/mL) in the range of 0.15 to 0.3M (NH.)2C03 when the concentration of hexamminecobalt(III) chloride is4kept at 0.04M. The Pu(IV) concentration increases, then, with increasing concentration of am-... 

The concentration of U(VI) ions in the supernatant increases with increasing concentrations of both ammonium carbonate and hexamminecobalt(III) chloride above 0.2M (NH CO and 0.02M [CoCNH JClg However, the concentration of U(VI) ions in the supernatant is more than 10 times lower than that of Pu(IV) ions. In this system, therefore, Pu(IV) and U(VI) ions can be separated from Am(III), Cm(III) and Np(V) ions,and 98% of the Pu(IV) or 99% of the U(VI) of the initial concentration( lmgAct/mL) can be recovered from the solution. Furthermore, as is well known,in ammonium carbonate solution alkali earth and transition metal elements precipitate forming carbonates or hydroxides and can thus be separated from actinide(IV) and (VI) ions. 

Actinide(III) precipitates dissolve to a limited extent in solution containing 1M (or more) (NH J CO. However, the actinide (I I I) carbonato complex ion precipitates very slowly by adding hexamminecobalt(III) chloride and the yield of precipitation is not high. Separations of actinide(IV) and (VI) ions from actinide (III) and (V) ions are thus achieved by taking advantage of their different solubilities in ammonium carbonate solution. Hexamminecobalt (III) salt is used as a precipitant to recover U(VI), Pu(IV) and Am(VI) ions from ammonium carbonate solution. 

Cyanometallates, syntheses 62, 67, 72, 73, 78 Hexamminecobalt(III) salts, synthesis 69 Cobalt nitrosyl tricarbonyl, S3mthesis 76 Tetrammineplatinum(II) chloride, synthesis 80... 

The crystals and carbon are filtered on a Buchner fxmnel and then added to a solution of 15 to 30 ml. of concentrated hydrochloric acid in 1500 ml. of water sufficient acid should be used to give the entire mixture an acid reaction. The mixture is heated on a hot plate to effect complete solution and is filtered hot. The hexamminecobalt(III) chloride is precipitated by adding 400 ml. of concentrated hydrochloric acid and slowly coohng to 0 . The precipitate is filtered, washed first with 60 per cent and then with 95 per cent alcohol, and dried at 80 to 100 . t Yield 230 g. (85 per cent). Anal. Calcd. for [Co(NH )6]Cls Co, 22.0 Cl, 39.8 NHs, 38.2. Found Co, 22.0 Cl, 39.8 NHj, 38.1. 

Hexamminecobalt(III) oxalate is prepared by adding a soluble oxalate to a solution of the chloride. The salt dried at 96° contains four mols of water. This precipitation is a quantitative method for determining the amount of hexamminecobalt(III) ion m a mixture. 

Hexamminecobalt(II) chloride, on the other hand, is not readily reduced by cobaltocene. Hence, its use in place of cobaltous chloride leads to higher yields of cobaltocene (55). 

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