Sodium bismuthate

Sodium bismuthate
Names
Other names
Sodium bismuth oxide
Identifiers
3D model (JSmol)
ECHA InfoCard 100.032.220
EC Number 235-455-6
Properties
NaBiO3
Molar mass 279.97 g/mol
Appearance Light brown powder
Density 6.50 g/cm3
insoluble in cold, decomposes in hot water
Hazards
Harmful (Xn)
R-phrases (outdated) R22, R36/37/38
S-phrases (outdated) S26, S36
Lethal dose or concentration (LD, LC):
420 mg/kg (rat)
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 bismuthate is the inorganic compound with the formula NaBiO3. It is a yellowish solid that is a strong oxidiser.[1] It is not soluble in cold water, which is sometimes convenient since the reagent can be easily removed after the reaction. It is one of the few sodium salts that is insoluble in water. It is commercially available however commercial samples may be a mixture of bismuth(V) oxide, sodium carbonate and sodium peroxide.[2] A related compound with the approximate formula Na3BiO4 also exists.[3]

Structure

Sodium bismuthate adopts an ilmenite structure, consisting of octahedral bismuth(V) centers and sodium cations. The average Bi-O distance is 2.116 Å. The ilmenite structure is related to the corundum structure (Al2O3) with a layer structure formed by close packed oxygen atoms with the two different cations alternating in octahedral sites.[4]

Synthesis and reactions

Vial of NaBiO3

Bismuth oxidizes to the +V oxidation state only with difficulty – the simple oxide Bi2O5 remains poorly characterized – and in the absence of alkali. The preparation of this salt involves oxidizing a mixture of Bi2O3 and Na2O with air (as the source of O2):[5]

Na2O + O2 + Bi2O3 → 2 NaBiO3

The procedure is analogous to the preparation oxidation of manganese dioxide in alkali to give sodium manganate.

Sodium bismuthate oxidizes water, decomposing into bismuth(III) oxide and sodium hydroxide:

2 NaBiO3 + H2O → 2 NaOH + Bi2O3 + O2

It is decomposed more rapidly by acids.

As a strong oxidizer, sodium bismuthate converts virtually any manganese compound to permanganate, which is easily assayed spectrophotometrically.[5] It is also used for lab-scale separation of plutonium.

References

  1. ↑ "Sodium bismuthate". Mallinckrodt Baker. June 19, 2007.
  2. ↑ Suzuki, Hitomi (2001). "Introduction". In Suzuki, Hitomi; Matano, Yoshihiro. Organobismuth Chemistry. Elsevier. pp. 1–20. ISBN 978-0-444-20528-5.
  3. ↑ Sascha, Vensky (2004). Konformationsaufklärung anorganischer Oxoanionen des Kohlenstoffs und Festkörpersynthesen durch Elektrokristallisation von Ag3O4 und Na3BiO4 (PDF) (Ph.D.) (in German). Max-Planck-Institut für Festkörperforschung, Stuttgart. doi:10.18419/opus-6540.
  4. ↑ Kumada, N.; Kinomura, N.; Sleight, A. W. (2000). "Neutron powder diffraction refinement of ilmenite-type bismuth oxides: ABiO3 (A = Na, Ag)". Materials Research Bulletin. 35 (14–15): 2397–2402. doi:10.1016/S0025-5408(00)00453-0.  – via ScienceDirect (Subscription may be required or content may be available in libraries.)
  5. 1 2 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
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