Xenon difluoride
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| Names | |
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IUPAC names
Xenon difluoride
Xenon(II) fluoride |
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| Identifiers | |
13709-36-9 
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| 3D model (Jmol) | Interactive image |
| ChemSpider |
75497
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| ECHA InfoCard | 100.033.850 |
| PubChem | 83674 |
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| Properties | |
| F2Xe | |
| Molar mass | 169.29 g·mol−1 |
| Appearance | White solid |
| Density | 4.32 g/cm3, solid |
| Melting point | 128.6 °C (263.5 °F; 401.8 K) |
| 25 g/l (0 °C) | |
| Vapor pressure | 6.0×102 Pa |
| Structure | |
| parallel linear XeF2 units | |
| Linear | |
| 0 D | |
| Thermochemistry | |
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Std molar
entropy (S |
254 J·mol−1·K−1 |
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Std enthalpy of
formation (ΔfH |
−108 kJ·mol−1 |
| Hazards | |
| Main hazards | Corrosive to exposed tissues. Releases toxic compounds on contact with moisture. |
| Safety data sheet | PELCHEM MSDS |
| NFPA 704 | |
| Related compounds | |
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Other anions
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Xenon dichloride |
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Other cations
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Krypton difluoride Radon difluoride |
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Related compounds
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Xenon tetrafluoride Xenon hexafluoride |
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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 | |
Xenon difluoride is a powerful fluorinating agent with the chemical formula XeF
2, and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with light or water vapor. Xenon difluoride is a dense, white crystalline solid. It has a nauseating odour and low vapor pressure.
Xenon difluoride is a linear molecule with an Xe–F bond length of 197.73±0.15 pm in the vapor stage, and 200 pm in the solid phase. The packing arrangement in solid XeF
2 shows that the fluorine atoms of neighbouring molecules avoid the equatorial region of each XeF
2 molecule. This agrees with the prediction of VSEPR theory, which predicts that there are 3 pairs of non-bonding electrons around the equatorial region of the xenon atom.
At high pressures, novel, non-molecular forms of xenon difluoride can be obtained. Under a pressure of ~50 GPa, XeF
2 transforms into a semiconductor consisting of XeF
4 units linked in a two-dimensional structure, like graphite. At even higher pressures, above 70 GPa, it becomes metallic, forming a three-dimensional structure containing XeF
8 units. However, a recent theoretical study has put these experimental results in doubt.
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