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Technetium(VII) oxide

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Technetium(VII) oxide

Structural formula of technetium(VII) oxide.
Unit cell of technetium(VII) oxide under standard conditions.
Unit cell of technetium(VII) oxide.
Names
IUPAC name
Technetium(VII) oxide
Other names
Technetium heptoxide
Identifiers
3D model (JSmol)
  • InChI=1S/7O.2Tc/q7*-2;2*+7
  • O=[Tc](=O)(=O)O[Tc](=O)(=O)=O
Properties
Tc2O7
Molar mass 307.810 g/mol
Appearance light yellow solid
Density 3.5 g/cm3
Melting point 119.5 °C (247.1 °F; 392.6 K)
Boiling point 310.6 °C (591.1 °F; 583.8 K)
hydrolysis to HTcO4
−40.0·10−6 cm3/mol
Structure[1]
Primitive orthorhombic
Pbca, No. 61
a = 1375.6 pm, b = 743.9 pm, c = 561.7 pm[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
radioactive
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Technetium (VII) oxide containing Technetium-99
Technetium (VII) oxide containing Technetium-99

Technetium(VII) oxide is the chemical compound with the formula Tc2O7. This yellow volatile solid is a rare example of a molecular binary metal oxide, the other examples being RuO4, OsO4, and the unstable Mn2O7. It adopts a centrosymmetric corner-shared bi-tetrahedral structure in which the terminal and bridging Tc−O bonds are 167pm and 184 pm respectively and the Tc−O−Tc angle is 180°.[2]

Technetium(VII) oxide is prepared by the oxidation of technetium at 450–500 °C:[3]

4 Tc + 7 O2 → 2 Tc2O7

It is the anhydride of pertechnetic acid and the precursor to sodium pertechnetate:

Tc2O7 + 2 H2O → 2 HTcO4
Tc2O7 + 2 NaOH → 2 NaTcO4 + H2O

References

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  1. ^ a b Krebs, Bernt (1971). "Technetium(VII)-oxid: Ein Übergangsmetalloxid mit Molekülstruktur im festen Zustand". Zeitschrift für anorganische und allgemeine Chemie. 380 (2): 146–159. doi:10.1002/zaac.19713800205.
  2. ^ Krebs, Bernt (1969). "Technetium(VII)-oxid: Ein Übergangsmetalloxid mit Molekülstruktur im festen Zustand". Angewandte Chemie. 81 (9): 328–329. Bibcode:1969AngCh..81..328K. doi:10.1002/ange.19690810905.
  3. ^ Herrell, A. Y.; Busey, R. H.; Gayer, K. H. (1977). Technetium(VII) Oxide, in Inorganic Syntheses. Vol. XVII. pp. 155–158. doi:10.1002/9780470132487.ch41. ISBN 0-07-044327-0.