Formula ReCl5 Density 4.9 g/cm³ Appearance red-brown ChemSpider ID 75428 | Molar mass 363.471 g/mol Melting point 220 °C Pubchem 83602 | |
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Rhenium pentachloride is an inorganic compound of chlorine and rhenium. The compound has the formula Re2Cl10 but it is usually referred to as the pentachloride. It is a red-brown solid. It is the highest chloride of rhenium.
Contents
Structure and preparation
Rhenium pentachloride has a bioctahedral structure and can be formulated as Cl4Re(μ-Cl)2ReCl4. The Re-Re distance is 3.74 Å. The motif is similar to that seen for tantalum pentachloride.
This compound was first prepared in 1933, a few years after the discovery of rhenium. The preparation involves chlorination of rhenium at temperatures up to 900 °C. The material can be purified by sublimation.
ReCl5 is one of the most oxidized binary chlorides of Re. With a d2 configuration, it could conceivably be further chlorinated, and indeed ReCl6 has been prepared, albeit indirectly from rhenium hexafluoride. Rhenium heptafluoride is known but not the heptachloride.
Uses and reactions
It degrades in air to a brown liquid.
Although rhenium pentachloride has no commercial applications, it is of historic significance as one of the early catalysts for olefin metathesis. Reduction gives Trirhenium nonachloride.
Oxygenation affords the Re(VII) oxychloride:
ReCl5 + 3 Cl2O → ReO3Cl + 5 Cl2