Sodium bismuthate is an inorganic compound, and a strong oxidiser with chemical formula NaBiO3.[3] It is somewhat hygroscopic,[2] but not soluble in cold water, which can be convenient since the reagent can be easily removed after the reaction. It is one of the few water insoluble sodium salts. Commercial samples may be a mixture of bismuth(V) oxide, sodium carbonate and sodium peroxide.[4]
 NaBiO3 powder.
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| Names | |
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| Other names
Sodium bismuth oxide
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.032.220 |
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| NaBiO3 | |
| Molar mass | 279.968 g/mol |
| Appearance | Yellow to yellowish-brown odorless powder[1] |
| Density | 6.50 g/cm3 |
| Insoluble in cold, decomposes in hot water[2] | |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H302, H315, H319, H335 | |
| P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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420 mg/kg (rat, oral)[1] |
| Related compounds | |
Other anions
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Sodium antimonate |
Other cations
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Potassium bismuthate |
Related compounds
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Sodium hexafluorobismuthate(V) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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A related compound with the approximate formula Na3BiO4 also exists.[5]
Structure
editSodium 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.[6]
Synthesis
editBismuth oxidizes to the +V oxidation state only with difficulty in the absence of alkali. Synthesis is performed by making a suspension of bismuth trioxide in a boiling sodium hydroxide solution. It is then oxidized by addition of bromine to form sodium bismuthate.[7]
- Bi2O3 + 6 NaOH + 2 Br2 → 2 NaBiO3 + 4 NaBr + 3 H2O
Another synthesis of NaBiO3 involves oxidizing a mixture of sodium oxide and bismuth(III) oxide with air (as the source of O2):[8]
- Na2O + Bi2O3 + O2 → 2 NaBiO3
The procedure is analogous to the oxidation of manganese dioxide in alkali to give sodium manganate.
Reactions
editStorage conditions with moisture and high temperatures are detrimental to sodium bismuthate, as it oxidizes water, decomposing into sodium hydroxide and bismuth(III) oxide:[2]
- 2 NaBiO3 + H2O → 2 NaOH + Bi2O3 + O2
It is decomposed faster by acids. In HCl, NaBiO3 also reacts to form chlorine gas.[2]
NaBiO3 may be used to detect manganese qualitatively and quantitatively. As a strong oxidizer, it converts almost any manganese compound to permanganate, which is easily assayed spectrophotometrically.[3] To do this, some NaBiO3 and the sample are reacted in a hot solution of sulfuric acid or nitric acid.[2] Permanganate has a violet color and maximum absorbance at 510 nm. The reaction is:[citation needed]
- 2 Mn2+ + 5 NaBiO3 + 14 H+ → 2 MnO−
4 + 5 Bi3+ + 5 Na+ + 7 H2O
Sodium bismuthate can perform oxidative 1,2-cleavage on glycols, ketols and alpha hydroxy acids with no further oxidation of the (possible) aldehyde products:[9]
- R2C(OH)–C(OH)–R2 → R2C=O + O=CR2
- R2C(OH)–C(O)–R → R2C=O + RCOOH
- R2C(OH)–COOH → R2C=O + CO2
These cleavages can be done in the presence of acetic or phosphoric acid at room temperature. Alcohols like methanol or ethanol can be used as the reaction media, as they are oxidized slowly with sodium bismuthate. Lead tetraacetate performs similar reactions, but anhydrous conditions, as required in the use of lead tetraacetate, are not necessary for sodium bismuthate.[9]
NaBiO3 can be used for lab-scale plutonium separation (see bismuth phosphate process).
Safety
editNaBiO3 is a mild mechanical irritant. Upon ingestion it is moderately toxic with symptoms akin to lead poisoning: abdominal pain and vomiting. Large doses cause diarrhea and death. Continued absorption of NaBiO3 into body causes permanent kidney damage.[1] These effects are due to the toxicity of bismuth. Oral absolute lethal dose (LD100) of NaBiO3 is 720 mg/kg for rats, and 510 mg/kg for rabbits.[10]
References
edit- Suzuki H, Matano Y, eds. (2001). Organobismuth Chemistry. doi:10.1016/B978-0-444-20528-5.X5000-9. ISBN 978-0-444-20528-5.
- Brauer G (1963). Handbook of Preparative Inorganic Chemistry. Vol. 1 (2 ed.). Academic Press. pp. 627–628.
Citations
edit- ^ a b c "Sodium bismuthate". Mallinckrodt Baker. 2007-06-19.
- ^ a b c d e The Merck index (12th ed.). Chapman & Hall Electronic Pub. Division. 2000. p. 1357. ISBN 9781584881292.
- ^ a b Greenwood NN, Earnshaw A (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Suzuki & Matano 2001, pp. 1–20.
- ^ Sascha V (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.
- ^ Kumada N, Kinomura N, Sleight A (November 2000). "Neutron powder diffraction refinement of ilmenite-type bismuth oxides: ABiO
3 (A = Na, Ag)". Materials Research Bulletin. 35 (14–15): 2397–2402. doi:10.1016/S0025-5408(00)00453-0. - ^ hrsg. von Georg Brauer. Unter Mitarb. von M. Baudler (1975). Handbuch der präparativen anorganischen Chemie / 1 (in German). Stuttgart: Enke. p. 604. ISBN 3-432-02328-6. OCLC 310719485.
- ^ Greenwood NN (1997). Chemistry of the elements (2nd ed.). Butterworth-Heinemann. p. 578. ISBN 9780080379418.
- ^ a b Suzuki & Matano 2001, p. 373.
- ^ European Commission. Directorate General for Health and Consumers. (2013). Opinion on bismuth citrate. Publications Office. doi:10.2772/74214. ISBN 978-92-79-30122-3.