Technetium(VI) fluoride
 |
|
| Identifiers | |
|---|---|
| Properties | |
| TcF6 | |
| Molar mass | 212 g/mol (98Tc) |
| Appearance | golden-yellow crystals |
| Density | 3,58 g/cm3 (−140 °C), solid |
| Melting point | 37.4 °C (99.3 °F; 310.5 K) |
| Boiling point | 55.3 °C (131.5 °F; 328.4 K) |
| Structure | |
| cubic | |
| Hazards | |
|
EU classification (DSD) (outdated)
|
not listed |
|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
|
 (what is   ?) |
|
| Infobox references | |
Technetium hexafluoride or technetium(VI) fluoride (TcF6) is a yellow inorganic compound with a low melting point. It was first identified in 1961. In this compound, technetium has an oxidation state of +6, the highest oxidation state found in the technetium halides. The other such compound is technetium(VI) chloride, TcCl6. In this respect, technetium differs from rhenium, which forms a heptafluoride, ReF7. Technetium hexafluoride occurs as an impurity in uranium hexafluoride, as technetium is a fission product of uranium.
Technetium hexafluoride is prepared by heating technetium metal with an excess of F2 at 400 °C.
Technetium hexafluoride is a golden-yellow solid at room temperature. Its melting point is 37.4 °C and its boiling point is 55.3 °C.
Technetium hexafluoride undergoes a solid phase transition at −4.54 °C. Above this temperature (measured at 10 °C), the solid structure is cubic. Lattice parameters are a = 6.16 Å. There are two formula units (in this case, discrete molecules) per unit cell, giving a density of 3.02 g·cm−3. Below this temperature (measured at −19 °C), the solid structure is orthorhombic space group Pnma. Lattice parameters are a = 9.55 Å, b = 8.74 Å, and c = 5.02 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 3.38 g·cm−3. At −140 °C, the solid structure is still orthothombic, but the lattice parameters are now a = 9.360 Å, b = 8.517 Å, and c = 4.934 Å, giving a density of 3.58 g·cm−3.
...
Wikipedia