SODIUM COBALTINITRITE is deep yellow to brown crystalline powder
SODIUM COBALTINITRITE is used in the detection Potassium.
For the detection of potassium with which it forms a slightly soluble compound.
Nitrosation reagent for the conversion of aromatic amines to 1,3-diaryltriazenes with excellent yield.1
Sodiumhexanitrocobaltate(III) ("sodiumcobaltinitrite") Na3Co(N02)6
is a well-known orange solid which precipitates potassium ions from aqueous solution as
K3Co(NO2)6. It is prepared by blowing air through a mixture of cobalt(II) nitrate and
sodium nitrite solutions in the presence of acetic acid:
2[Co(H20)6]2+ +12NO2- +2CH3COOH + 1/2O2 → 2[Co(NO)2)6]3- +2CH3COO-+ 13H2O
after filtration of any precipitated potassium or ammonium salts, the sodium salt is precipitated
by the addition of ethanol.
Dissolve the salt (ca 60g) in H2O (300mL), filter to obtain a clear solution, add 96% EtOH (250mL) with vigorous stirring. Allow the precipitate to settle for 2hours, filter it off, wash it with EtOH (4 x 25mL), twice with Et2O and dry it in air [Glemser in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p 1541 1965]. It forms yellow to brown crystals which are very soluble in H2O, are decomposed by acid and form an insoluble K salt. Used for estimating potassium.
