Sodium bismuthate

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Sodium bismuthate
Names
IUPAC name
Sodium bismuthate
Other names
Sodium bismuth oxide
Sodium bismuth trioxide
Properties
NaBiO3
Molar mass 279.968 g/mol
Appearance Yellow to yellowish-brown powder
Odor Odorless
Density 6.50 g/cm3
Insoluble in cold water
Reacts with hot water
Solubility Reacts with acids
Insoluble in most solvents
Vapor pressure ~0 mmHg
Thermochemistry
-686 kJ/mol[1]
Hazards
Safety data sheet Sifma-Aldrich (80%)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
420 mg/kg (rat, oral)
Related compounds
Related compounds
Potassium bismuthate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium bismuthate is an inorganic chemical compound, a strong oxidizer with chemical formula NaBiO3.

The compound is rarely available pure, and commercial samples may also contain a mixture of bismuth trioxide, sodium carbonate and sodium peroxide. A related compound with the approximate formula Na3BiO4 also exists.

Properties

Chemical

Sodium bismuthate is sensitive to moisture and will slowly decompose upon contact.[2]

2 NaBiO3 + H2O → 2 NaOH + Bi2O3 + O2

In contact with a haloacid it will release its respective halogen. For example, reaction with hydrochloric acid will produce chlorine gas:

NaBiO3 + 6 HCl → NaCl + BiCl3 + Cl2

This reaction is similar to the reaction between potassium permanganate with HCl.

Sodium bismuthate is a very strong oxidizer, capable of converting almost any manganese compound to permanganate. The reaction takes place in a hot solution of sulfuric acid or nitric acid.

2 Mn2+ + 5 NaBiO3 + 14 H+ → 2 MnO4 + 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. 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.

Physical

Sodium bismuthate is a yellow-brown powdered solid, insoluble in cold water and decomposes in hot water.

Availability

Sodium bismuthate is sold by chemical suppliers.

Preparation

First, a suspension of bismuth trioxide in a boiling aq. sodium hydroxide is created. Liquid bromine is added to this hot suspension, which yields sodium bismuthate.[3]

Bi2O3 + 6 NaOH + 2 Br2 → 2 NaBiO3 + 4 NaBr + 3 H2O

The solution in then cooled, to slow the decomposition of the compound. As sodium bismuthate is poorly soluble in water, the resulting product can be easily filtered off.

Another convenient route involves oxidizing bismuth(III) nitrate with sodium persulfate and neutralizing the solution with sodium hydroxide.[4]

A water-free synthesis route involves oxidizing a molten mixture of sodium oxide and bismuth(III) oxide with air (as the source of O2):[5]

Na2O + Bi2O3 + O2 → 2 NaBiO3

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

Projects

  • Oxidizing agent
  • Test for manganese
  • Make permanganate
  • Compound collecting
  • Separation of actinides (Am, Pu, etc.)

Handling

Safety

NaBiO3 is a irritant if inhaled. Continued absorption of NaBiO3 into body causes permanent kidney damage.

Storage

In closed plastic or glass bottles, away from moisture and acids.

Disposal

Can be neutralized by exposure to hot water or hydrogen peroxide and the bismuth recycled.

References

  1. Kasenov; Zhambekov; Kasenova; Russian Journal of Physical Chemistry; vol. 71; nb. 6; (1997); p. 1024 - 1026
  2. The Merck index (12th ed.). Chapman & Hall Electronic Pub. Division. 2000. p. 1357
  3. The Handbook of Preparative Inorganic Chemistry, edited by Georg Brauer. Volume 1 page 627-628
  4. https://www.youtube.com/watch?v=wMPYGLEqqoc
  5. Greenwood NN (1997). Chemistry of the elements (2nd ed.). Butterworth-Heinemann. p. 578

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