Sodium cobaltinitrite

Sodium cobaltinitrite

Names
IUPAC name sodium hexanitritocobaltate(III)
Identifiers
CAS Number	13600-98-1
ChemSpider	13198283
Jmol 3D model	Interactive image
PubChem	16211641
InChI InChI=1S/Co.6NO2.3Na/c;6*2-1-3;;;/q-3;;;;;;;3*+1 Key: IMBXIBFCGMYSME-UHFFFAOYSA-N InChI=1/Co.6NO2.3Na/c;6*2-1-3;;;/q-3;;;;;;;3*+1/rCoN6O12.3Na/c8-2(9)1(3(10)11,4(12)13,5(14)15,6(16)17)7(18)19;;;/q-3;3*+1 Key: IMBXIBFCGMYSME-PEVTYUNUAJ
SMILES [Na+].[Na+].[Na+].O=[N+]([O-])[Co-3]([N+]([O-])=O)([N+](=O)[O-])([N+]([O-])=O)([N+]([O-])=O)[N+]([O-])=O
Properties
Chemical formula	CoN6Na3O12
Molar mass	403.93 g·mol^−1
Hazards
Safety data sheet	JT Baker MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Sodium cobaltinitrite is a coordination compound with the formula Na₃Co(NO₂)₆. The anion of this yellow-coloured salt consists of a cobalt(III) center N-bonded to six nitrito ligands. It is a reagent for the qualitative test for potassium and ammonium ions.^[1]

Synthesis and reactions

The compound is prepared by oxidation of cobalt(II) salts in the presence of sodium nitrite:^[2]

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.^[3] In geochemical analysis, sodium cobaltinitrite is used to distinguish alkali feldspars from plagioclase feldspars in thin section.^[4]

See also

• Potassium cobaltinitrite

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
2. Glemser, O. (1963). "Sodium Hexanitritocobaltate(III)". In Brauer, G. Handbook of Preparative Inorganic Chemistry 1 (2nd ed.). New York, NY: Academic Press. p. 1541.
3. Vogel, A. I. (1951). Quantitative Inorganic Analysis (2nd ed.). Longmans Green and Co.
4. 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.