Zirconium(IV) fluoride
Zirconium(IV) fluoride
Names
IUPAC names
Zirconium(IV) fluoride
Zirconium tetrafluoride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.107
EC Number
  • 232-018-1
UNII
  • InChI=1S/4FH.Zr/h4*1H;/q;;;;+4/p-4 checkY
    Key: OMQSJNWFFJOIMO-UHFFFAOYSA-J checkY
  • InChI=1/4FH.Zr/h4*1H;/q;;;;+4/p-4
    Key: OMQSJNWFFJOIMO-XBHQNQODAN
  • F[Zr](F)(F)F
Properties
ZrF4
Molar mass 167.21 g/mol
Appearance white crystalline powder
Density 4.43 g/cm3 (20 °C)
Melting point 910 °C (1,670 °F; 1,180 K)
1.32 g/100mL (20 °C)
1.388 g/100mL (25 °C)
Structure
Monoclinic, mS60
C12/c1, No. 15
Hazards
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
98 mg/kg (oral, mouse)
98 mg/kg (oral, rat)[1]
Related compounds
Other anions
 Zirconium(IV) chloride
Zirconium(IV) bromide
Zirconium(IV) iodide
Other cations
 Titanium(IV) fluoride
Hafnium(IV) fluoride
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

Zirconium(IV) fluoride describes members of a family inorganic compounds with the formula (ZrF4(H2O)x. All are colorless, diamagnetic solids. Anhydrous Zirconium(IV) fluoride' is a component of ZBLAN fluoride glass.[2]

Structure

Tetragonal ZrF4

Three crystalline phases of ZrF4 have been reported, α (monoclinic), β (tetragonal, Pearson symbol tP40, space group P42/m, No 84) and γ (unknown structure). β and γ phases are unstable and irreversibly transform into the α phase at 400 °C.[3]

Zirconium(IV) fluoride forms several hydrates. The trihydrate has the structure (μ−F)2[ZrF3(H20)3]2.[4]

Preparation and reactions

Zirconium fluoride can be produced by several methods. Zirconium dioxide reacts with hydrogen fluoride and hydrofluoric acid to afford the anhydrous and monohydrates:

ZrO2 + 4 HF → ZrF4 + 2 H2O

The reaction of Zr metal reacts at high temperatures with HF as well:

Zr + 4 HF → ZrF4 + 2 H2

Zirconium dioxide reacts at 200 °C with solid ammonium bifluoride to give the heptafluorozirconate salt, which can be converted to the tetrafluoride at 500 °C:

2ZrO2 + 7 (NH4)HF2 → 2 (NH4)3ZrF7 + 4 H2O + NH3
(NH4)3ZrF7 → ZrF4 + 3 HF + 3 NH3

Addition of hydrofluoric acid to solutions of zirconium nitrate precipitates solid monohydrate. Hydrates of zirconium tetrafluoride can be dehydrated by heating under a stream of hydrogen fluoride.

Zirconium fluoride can be purified by distillation or sublimation.[2]

Zirconium fluoride forms double salts with other fluorides. The most prominent is potassium hexafluorozironate, formed by fusion of potassium fluoride and zirconium tetrafluoride:[5]

ZrF4 + 2 KF → K2ZrF6

Applications

The major and perhaps only commercial application of zirconium fluoride is as a precursor to ZBLAN glasses.[2]

Mixture of sodium fluoride, zirconium fluoride, and uranium tetrafluoride (53-41-6 mol.%) was used as a coolant in the Aircraft Reactor Experiment. A mixture of lithium fluoride, beryllium fluoride, zirconium fluoride, and uranium-233 tetrafluoride was used in the Molten-Salt Reactor Experiment. (Uranium-233 is used in the thorium fuel cycle reactors.)

References

  1. ↑ "Zirconium compounds (as Zr)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  2. 1 2 3 Nielsen, Ralph (2000). "Zirconium and Zirconium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a28_543. ISBN 3527306730.
  3. ↑ Paul L. Brown; Federico J. Mompean; Jane Perrone; Myriam Illemassène (2005). Chemical thermodynamics of zirconium. Gulf Professional Publishing. p. 144. ISBN 0-444-51803-7.
  4. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 965. ISBN 978-0-08-037941-8.
  5. ↑ Meshri, Dayal T. (2000), "Fluorine compounds, inorganic, titanium", Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley, doi:10.1002/0471238961.2009200113051908.a01, ISBN 9780471238966
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