Sodium_cobaltinitrite

Sodium hexanitritocobaltate(III)

Sodium hexanitritocobaltate(III)

Chemical compound

Sodium hexanitritocobaltate(III) is inorganic compound with the formula Na3[Co(NO2)6]. The anion of this yellow-coloured salt consists of the transition metal nitrite complex [Co(NO2)6]3−. It was a reagent for the qualitative test for potassium and ammonium ions.[2]

Quick Facts Names, Identifiers ...

Synthesis and reactions

The compound is prepared by oxidation of cobalt(II) salts in the presence of sodium nitrite:[3]

4 [Co(H2O)6](NO3)2 + O2 + 24 NaNO2 → 4 Na3[Co(NO2)6] + 8 NaNO3 + 4 NaOH + 22 H2O

Application for analysis of potassium

Although the sodium cobaltinitrite is soluble in water, it forms the basis of a quantitative determination of potassium, thallium, and ammonium ions. Under the recommended reaction conditions the insoluble double salt, K2Na[Co(NO2)6]·H2O is precipitated and weighed.[4][page needed] In geochemical analysis, sodium cobaltinitrite is used to distinguish alkali feldspars from plagioclase feldspars in thin section.[5]

  • Concentrated aqueous solution of sodium cobaltinitrite.
  • K2Na[Co(NO2)6]·H2O
Fragment of the Na3Co(NO2)6 lattice, highlighting the CoN6 and NaO6 coordination spheres.[6]

See also

References

  1. [1]
    "C&L Inventory". echa.europa.eu.
  2. [2]
    Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  3. [3]
    Glemser, O. (1963). "Sodium Hexanitritocobaltate(III)". In Brauer, G. (ed.). Handbook of Preparative Inorganic Chemistry. Vol. 1 (2nd ed.). New York, NY: Academic Press. p. 1541.
  4. [4]
    Vogel, A. I. (1951). Quantitative Inorganic Analysis (2nd ed.). Longmans Green and Co.
  5. [5]
    Bailey, E. H.; Stevens, R. E. (1960). "Selective staining of K-feldspar and plagioclase on rock slabs and thin sections". American Mineralogist. 45: 1020–1025. ISSN 1945-3027.
  6. [6]
    Brian N. Figgis; Alexandre N. Soboleva (2001). "Na3Co(NO2)6 at 293 and 10 K". Acta Crystallographica Section C. 57 (Pt 8): 885–886. doi:10.1107/S0108270101007995. PMID 11498599.


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