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Rhenium pentachloride

Rhenium pentachloride
Systematic name Rhenium pentachloride
Other names Rhenium(V) chloride, Rhenium chloride, pentachlororhenium
Molecular formula ReCl5
Molar mass 363.471 g/mol
Appearance red-brown
CAS number [13596-35-5]
Density and phase 4.9 g/cm3, solid
Magnetic Susceptibility 1225 X 10-6 cm3 ml-1
Vapor Pressure N/A
Solubility in water Will react to decompose and release HCl (g)
Melting point 220 °C
Boiling point N/A
Acidity (pKa) N/A
Viscosity N/A
Molecular shape Octahedral
Crystal structure double hexagonally closed packed
R/S statement R: 36, 37, 38
Main hazards Highly Air Sensitive, will decompose to form HCl(g)
NFPA 704
Related compounds
Other anions Rhenium hexathiocyanate, Rhenium tetraiodate, Rhenium hexafluoride
Related compounds Rhenium trichloride, Rhenium tetrachloride, Rhenium hexachloride  ?
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Rhenium pentachloride is a compound of rhenium and chlorine.



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


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.


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


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


  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
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Rhenium_pentachloride". A list of authors is available in Wikipedia.
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