- Rhenium trioxide
ImageFile = Rhenium-trioxide-3D-vdW.png
Section1 = Chembox Identifiers
Section2 = Chembox Properties
Formula = ReO3
MolarMass = 234.21 g mol−1
Section3 = Chembox Hazards
Rhenium oxide forms crystals with a primitive cubic unit cell, with a lattice parameter of 3.742 Å (374.2 pm). The structure of ReO3 is similar to the
Perovskitestructure (ABO3), without the large A cation at the centre of the unit cell. Each rhenium atom is surrounded by six oxygen atoms, forming a ReO6 octahedron. These octahedra share corners to form the 3-dimensional structure [S.J. Heyes (2000) [http://www.ncl.ox.ac.uk/icl/heyes/structure_of_solids/Lecture4/Lec4.html#anchor3 "Structures of Simple Inorganic Solids"] , Department of Chemistry, University of Oxford.] .
Upon viewing a unit cell of ReO3, one can see that it is composed of eight ⅛ fragments of rhenium atoms, and twelve ¼ fragments of oxygen atoms. These numbers reduce to 1 Re and 3 O, hence the formula of ReO3. The coordination number of Re in this compound is 6 because each rhenium atom has six neighbouring oxygen atoms which bear opposite charge. The coordination number of O in this compound is 2 because each oxygen atom has 2 neighbouring Re atoms of opposite charge.
ReO3 is unusual for an oxide because it exhibits very low
resistivity. It behaves more like a metalin that its resistivity decreases as its temperature decreases. At 300 K, its resisitivity is 100.0 nΩ·m, whereas at 100 K, this decreases to 6.0 nΩ·m, 17 times less than at 300 K.
Rhenium trioxide can be formed by reducing
rhenium(VII) oxidewith carbon monoxideGreenwood&Earnshaw, p. 1047.] :
:Re2O7 + CO → 2ReO3 + CO2
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