Rhenium pentachloride

Rhenium pentachloride is a compound of rhenium and chlorine.

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History

Rhenium pentachloride was first discovered by Geilmann, Wilhelm, and Friedrich in 1933.¹ It is a red-brown solid that is very air sensitive and will release HCl(g) when reacted with water.

Structure and physical properties

Rhenium pentachloride was found to exist as a solid in the form of Re₂Cl₁₀.² It has a melting point of 220 degrees Celsius and is a paramagnetic molecule.³ There has been no report of a boiling point for this compound. Rhenium pentachloride is a double hexagonally closed packed structure.²

Chemical properties

Rhenium pentachloride is very air sensitive. Leaving it out overnight in atmosphere will lead to a brown liquid.²

By composition chemical composition:

Re: 51.23%

Cl: 48.77%

The formal charges are as follows:

Re: V

Cl: -I

It can react to form lower oxidation state chlorides such as rhenium trichloride.

ReCl₅ → ReCl₃

It can also react with neutral and anionic donors to form complexed species.

ReCl₅ + 6CNS^- → [Re(CNS)₆]^-

It is also reactive enough to react with solvents such as ammonia:

ReCl₅ + NH₃ (excess) → ReCl₃(NH₂)₂

Preparation

The preparation of this can be found by the chlorination of Rhenium at 500 degrees Celsius.¹ The purification of this material is done through multiple sublimations. The reaction leads to only one side product ReCl₃. Synthesis of ReCl₄ and ReCl₆ must be done by other means.

Uses

Due to its reactivity ReCl₅ is not biologically active. This will react with water to form HCl(g). However it can be used to make compounds such as Cp₂ReH which similar to nickelocene can act as a catalyst to react with olefins.⁴ An example of this catalytic activity is in the formation of polymers using ReCl₅.⁵

This compound is highly reactive and as mentioned previously can react to form lower oxidation states such as rhenium trichloride, which has catalytic activity for a wide variety of applications. An example is the following reaction⁷:

ReCl₅ + 3 Cl₂O → ReO₃Cl + 5 Cl₂

Safety

When handling use dry conditions as the compound is very reactive. After inhalation seek medical attention immediately and stay in ventilated areas. After skin contact rinse area with water can

References

1. Geilmann, Wilhelm; Wrigge, Friedrich W.; Biltz, Wilhelm. Z. anorg. allgem. Chem. 1933, 214, 244.
2. Edwards, D. A.; Ward, R. T. Journal of the Chemical Society [Section] A: Inorganic, Physical, Theoretical 1970 , 9, 1617.
3. CRC Handbook Online Edition
4. Mucker, K.; Smith, G.S.; Johnson, Q. Acta Cryst. 1968 B, 24, 874.
5. Hamilton, J.G.; Iving, K.J.; Rooney, J.J.; Journal of Molecular Catalysis 1986 , 36, 115
6. Alfa Aesar’s MSDS
7. Housecroft, C.E., Sharpe, A.G., Inorganic Chemistry, 2nd ed., Pearson Education Limited: Essex, England