Potassium hexanitrocobaltate III

Potassium Hexanitrocobaltate(III). Add a little acetic acid and an excess of potassium nitrite to a cobalt(II) salt solution. Heat the mixture. What gas evolves What precipitates Write the equation of the reaction. What is the coordination number of cobalt in this compound ... 

III) nitrate cis-[Co en2(N02)2]NC>3, N 29.44%. Brown-yell cryst, may be prepd by treating potassium hexanitrocobaltate (III) with dil aq soln of ethylenediamine (abbr en), C2H4(NH2)2, followed by heating and cooling. The resulting nitrite cis-[Co en2(N02)2]N02 was oxidized to nitrate by treatment with coned HNO3... 

Sodium hexanitrocobaltate (III) (Na3[Co(N02)6]) Tartaric acid solution (sodium acetate buffered) Yellow precipitate of potassium hexanitrocobaltate (III) insoluble in acetic acid White precipitate of potassium hydrogen tartrate... 

Werner1,3 prepared as-dinitrobis(ethylenediamine)co-balt(III) nitrate by heating ethylenediamine with potassium hexanitrocobaltate(III) to give the dinitrobis(ethylenedia-mine)cobalt(III) nitrite, followed by conversion to the nitrate with nitric acid. The procedure given here for the cis compound utilizes this method. 

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. 

Several preparations of salts of the czs-dinitrobis(ethyl-enediamine)cobalt(III) ion have been reported in the literature. The most usual is that of Werner/ modified by Holtzclaw, Sheetz, and McCarty, beginning with potassium hexanitrocobaltate(III). However, this method makes use of a starting material which is difficult to prepare in high purity and to dry thoroughly, involves critical temperature control, and produces a yield of about 15%. The following procedure, which utilizes ethylenedi-amine)cobalt(III) chloride as the starting material, provides a 60% yield of cfs-dinitrobis(ethylenediamine)cobalt-(III) nitrite. The nitrite is then easily converted to the nitrate. 

Cobaltinitrites are also complexes of Co. Addition of KNO2 to a Co solution made acid with acetic acid gives a yellow precipitate of potassium hexanitrocobaltate(III), K3Co(N02)g ... 

For analysis, the red product is dissolved in water. The resulting red solution is decolorized with oxygen and made slightly acidic with nitric acid. Aliquot portions of the solution are analyzed for potassium by precipitation of potassium hexanitrocobaltate(III), for cyanide by precipitation of silver cyanide, and for nickel by precipitation of the dime thy lgly oxime derivative. Anal. Calcd. for K4[Ni2(CN)6] K, 36.3 Ni, 27.3 CN, 36.4. Found K, 36.0 Ni, 27.1 CN, 35.8. 

Synonyms Cl pigment yellow 40 Cobaltic potassium nitrite Cobalt yellow Fischer s salt Potassium cobaltnitrate Potassium hexanitrocobaltate III... 

Potassium hexanitrocobaltate III. See Cobalt potassium nitrite Potassium hyaluronate CAS 31799-91-4... 

The yellow pigment tripotassium hexanitrocobalt(III) (K3Co(N02)6.wH20) and dipotassium monosodium hexanitro-cobalt(III) (K2NaCo(N02)e.wH20) are also classed here as cobalt nitrates. See the entries for cobalt red, cobalt yellow and potassium hexanitrocobalt(III) for ftirther information. 

Potassium hexanitrocobalt(III) Aureolin Cobalt yellow Carlyle (2001) 262, 526 Heaton (1928) 383... 

Twenty grams of sodium hexanitrocobaltate (III) (No. 7S) are dissolved in 200ml of water and 15g of potassium acetate in 100ml of water are added. The light-yellow potassium salt that precipitates immediately is washed on the filter with alcohol and acetone. 

Practice Problem A Write the formulas for (a) pentaaquabromoruthenium(II) nitrate, (b) potassium tetrabromodichloroplatinate(IV), and (c) sodium hexanitrocobaltate(III). 

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