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|Jmol-3D images||Image 1|
|Molar mass||93.84 g/mol (anhydrous)
165.k90 g/mol (tetrahydrate)
|Appearance||red-violet transparent crystal|
|Density||4.09 g/cm3 (anhydrous)
2.20 g/cm3 (tetrahydrate)
|Melting point||970 °C (anhydrous)
100 °C (tetrahydrate)
|Boiling point||1100 °C (anhydrous)|
|Solubility in water||165 g/100 mL|
|Solubility||insoluble in ethanol, ether;
dissolves in HF
|Crystal structure||Rutile (tetragonal), tP6|
|Space group||P42/mnm, No. 136|
|Main hazards||Causes severe skin burns & eye damage;
Hazardous decomposition products formed under fire conditions- Iron oxides
|Flash point||not applicable|
|Other anions||iron(II) oxide, iron(II) chloride|
|Other cations||manganese(II) fluoride, cobalt(II) fluoride|
|Related compounds||iron(III) fluoride|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Iron(II) fluoride (also ferrous fluoride) is a chemical compound with formula FeF2. It is a green crystalline solid that melts at about 1000 °C. It is used in ceramics and as a catalyst in some organic reactions.
Through neutron diffraction studies at low temperatures, Iron(II) fluoride is antiferromagnetic. Heat capacity was measured over a temperature range 12-300 K. At temperature 78.3 K a thermal anomaly occurred. This thermal anomaly can be explained as Iron(II) fluoride passing from its disordered paramagnetic state to a more ordered antiferromagnetic state.
The vapor species were identified between 965 and 1149 K. Using mass spectrometry the heat of sublimation was experimentally determined and averaged to be 75.56 ± 0.23 kcal. mole−1. The following reaction was proposed in order to calculate the atomization energy for Fe+:
- FeF2 + e → Fe+ +F2(or 2F) + 2e
It is slightly soluble in water (Ksp = 2.36 × 10−6) and can be crystallized from it as a colorless tetrahydrate, FeF2·4H2O, (CAS Number 13940-89-1). The latter exists in two crystal structures, one rhombohedral and one hexagonal, the former having a disordered The tetrahydrate oxidizes in moist air to a hydrate of iron(III) fluoride, 2FeF3·9H2O.
To determine impurities in previous crystal structuring of the FeF2 the compound was first melted and then through spectrochemical analysis the percent of impurities could be determined.
- d1(Fe-F): 2.03 ± 0.07 Å
- d2(Fe-F): 2.10 ± 0.04 Å
- d (F-F): 2.59 ± 0.13 Å
- Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
- Sigma-Aldrich. "Material Safety Data Sheet". Sigma-Aldrich. Retrieved 5 April 2011.
- Iron (II) Fluoride in the Chembok site. Accessed on 2011-01-16.
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419.
- Erickson, R. (June 1953). "Neutron Diffraction Studies of Antiferromagnetism in Manganous Fluoride and Some Isomorphous Compounds". Physical Review 90 (5): 779–785. doi:10.1103/PhysRev.90.779.
- Stout, J.; Edward Catalano (December 1953). "Thermal Anomalies Associated with the Antiferromagnetic Ordering of FeF2, CoF3, and NiF2". Physical Review 92 (6): 1575–1575. doi:10.1103/PhysRev.92.1575.
- Kent, Richard; John L. Margrave (November 1965). "Mass Spectrometric Studies at High Temperatures. VIII. The Sublimation Pressure of Iron(II) Fluoride". Journal of the American Chemical Society 87 (21): 4754–4756. doi:10.1021/ja00949a016.
- Ksp solubility constant for common salts. Solubility of things site. Accessed on 2011-01-16.
- Penfold, B. R.; Taylor, M. R. (1960). "The crystal structure of a disordered form of iron(II) fluoride tetrahydrate". Acta Crystallographica 13: 953–956. doi:10.1107/S0365110X60002302.
- Stout, J.; Stanley A. Reed (Nov 5, 1954). "The Crystal Structure of MnF2, FeF2, CoF2, NiF2 and ZnF2". Crystal Structures of Anhydrous Fluorides: 5279–5281.