Sodium hexafluoroaluminate

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Sodium hexafluoroaluminate
Cryolite impure sample.jpg
Impure powdered cryolite, or "greyolite"
Names
IUPAC name
Sodium hexafluoroaluminate
Other names
Cryolite
Kryolite
Sodium aluminium hexafluoride
Sodium fluoroaluminate
Trisodium hexafluoroaluminate
Properties
Na3AlF6
Molar mass 209.94 g/mol
Appearance White solid
Odor Odorless
Density 2.9 g/cm3
Melting point 950 °C (1,740 °F; 1,220 K)
Boiling point Decomposes
0.042 g/100 ml (25 °C)
Solubility Insoluble in organic solvents
Vapor pressure ~0 mmHg
Thermochemistry
-3,253.6 kJ/kmol[1]
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
5,000 mg/kg (rat, oral)
Related compounds
Related compounds
Sodium fluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium hexafluoroaluminate or sodium aluminium hexafluoride is the inorganic compound with the formula Na3AlF6. It occurs naturally as the mineral cryolite, which is also the more common name for this compound.

Properties

Chemical

Molten cryolite will dissolve aluminium oxide and the electrolysis of this mixture will give aluminium metal.

Physical

Sodium hexafluoroaluminate is a white solid, insoluble in water or other solvents.

Availability

Sodium hexafluoroaluminate is sold by various chemical suppliers. Can also be bought online.

Natural cryolite can be found in various parts of the world, such as Greenland or several US states.

Preparation

Cryolite is produced by reacting sodium hydroxide with aluminium oxide and hydrofluoric acid. Cryolite precipitates out of the solution, due to its very low solubility.

Projects

  • Source of fluorides
  • Make aluminium metal (Hall–Héroult process)
  • Mineral collecting

Handling

Safety

Sodium hexafluoroaluminate has relative low toxicity. It is often used as roach killer.

Storage

Cryolite doesn't require special storage conditions. Any clean plastic bottle can be used as storage container.

Disposal

Cryolite doesn't require special disposal. Can be dumped in the trash.

References

  1. Sterten, A.; Maeland, I.; Acta Chemica Scandinavica, Series A: Physical and Inorganic Chemistry; vol. 39; (1985); p. 241 - 258

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