Potassium dinitrodiglycinatocobaltate III

The method previously described for the preparation of potassium dinitrodiglycinatocobaltate(III) uses the action of potassium glycinate on potassium hexanitrocobaltate-(III) The corresponding silver salt is prepared by double decomposition of the potassium salt with silver nitrate. 

The brown crystalline potassium dinitrodiglycinatocobal-tate(III) (ca. 16 g,) is filtered on a Buchner funnel and washed successively with 50% ethanol, 96% ethanol, and ether, (The checkers suggest no more than 15 ml, of ice-cold 50% ethanol,) The filtrate obtained is evaporated to about 30 ml, at room temperature in vacuo. After it is kept in a refrigerator overnight, an additional amount of the complex salt is obtained. The total yield amounts to about 22 g, (65%), (The checkers report 24,5 g, yield,) 

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A solution of 3,7 g, (0,022 mol) of silver nitrate in 15 ml, of water is added to a solution of 6,8 g, (0,02 mol) of potassium dinitrodiglycinatocobaltate(III) in 65 ml, of water. The orange-brown precipitate is filtered with suction and washed successively with water, ethanol, and ether. Yield 7,3 g, (90%), The salt may be recrystallized from 700 to... 

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