Cobaltate , sodium potassium dihydrate

In another spectrophotometric procedure Motomizu [224] adds to the sample (2 litres) 40% (w/v) sodium citrate dihydrate solution (10 ml) and a 0.2% solution of 2-ethylamino-5-nitrosophenol in 0.01 M hydrochloric acid (20 ml). After 30 min, add 10% aqueous EDTA (10 ml) and 1,2-dichloroethane (20 ml), mechanically shake the mixture for 10 minutes, separate the organic phase and wash it successively with hydrochloric acid (1 2) (3 x 5 ml), potassium hydroxide (5 ml), and hydrochloric acid (1 2) (5 ml). Filter, and measure the extinction at 462 nm in a 50 mm cell. Determine the reagent blank by adding EDTA solution before the citrate solution. The sample is either set aside for about 1 day before analysis (the organic extract should then be centrifuged), or preferably it is passed through a 0.45 xm membrane-filter. The optimum pH range for samples is 5.5 - 7.5. From 0.07 to 0.12 p,g/l of cobalt was determined there is no interference from species commonly present in seawater. 

It has been established by X-ray analysis that in potassium (-b)58 -tris-(l,10-phenanthroline)nickel(ii) (—)5g,-trisoxalatocobaltate(m) dihydrate both complex ions have the A configuration. The mean Co-O distance is 1.93 A. The complex anion in sodium (- -)s4,-bismaIonatoethylenediamine-cobaltate(iii) has the A configuration the six-membered malonato chelate rings adopt boat conformations. ... 

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