Rhenium(IV) oxide

Rhenium(IV) oxide or rhenium dioxide is the inorganic compound with the formula ReO₂. This gray to black crystalline solid is a laboratory reagent that can be used as a catalyst. It adopts the rutile structure.

Rhenium(IV) oxide

Re   O
Names
IUPAC name Rhenium(IV) oxide
Other names Rhenium dioxide
Identifiers
CAS Number	12036-09-8 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.031.659
EC Number	234-839-0
PubChem CID	82847
CompTox Dashboard (EPA)	DTXSID5065192
InChI InChI=1S/2O.Re
SMILES O=[Re]=O
Properties
Chemical formula	ReO2
Molar mass	218.206 g/mol
Appearance	gray orthorhombic crystals
Density	11.4 g/cm3[1]
Melting point	decomposes at 1000 °C[2]
Solubility in water	insoluble
Solubility in alkali	insoluble
Magnetic susceptibility (χ)	+44.0·10−6 cm3/mol
Structure
Crystal structure	Orthorohmbic, oP12
Space group	Pbcn, No. 60
Hazards
NFPA 704 (fire diamond)	1 0 0
Safety data sheet (SDS)	Aldrich MSDS
Related compounds
Other anions	Rhenium(VII) oxide Rhenium(III) oxide Rhenium(III) chloride
Other cations	manganese(IV) oxide Technetium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis and reactions

It forms via comproportionation:^[3]

2 Re₂O₇ + 3 Re → 7 ReO₂

Single crystals are obtained by chemical transport, using iodine as the transporting agent.:^[4]

ReO₂ + I₂ ⇌ ReO₂I₂

At high temperatures it undergoes disproportionation:

7 ReO₂ → 2 Re₂O₇ + 3 Re

It forms rhenates with alkaline hydrogen peroxide and oxidizing acids.^[5] In molten sodium hydroxide it forms sodium rhenate:^[6]

2 NaOH + ReO₂ → Na₂ReO₃ + H₂O