Trirhenium nonachloride

Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents. The compound is important in the history of inorganic chemistry as an early example of a cluster compound with metal-metal bonds.[1] It is used as a starting material for synthesis of other rhenium complexes.

Trirhenium nonachloride
Re3Cl12 cluster subunit in ReCl3
Names
IUPAC name
Rhenium(III) chloride
Other names
Rhenium trichloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.033.610
EC Number
  • 236-987-1
  • InChI=1S/3ClH.Re/h3*1H;/q;;;+3/p-3
  • Cl[Re](Cl)Cl
Properties
ReCl3
Molar mass 292.57 g/mol
Appearance red, crystalline, nonvolatile solid
Density 4800 kg/m3
Melting point N/A
Boiling point 500 °C (932 °F; 773 K) (decomposes)
hydrolyzes to form Re2O3.xH2O.
Structure
Rhombohedral, hR72
R-3m, No. 166
(trimeric solid and in solution)
(dimeric in acetic acid)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Corrosive (C)
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
 Rhenium tribromide
Rhenium triiodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Infobox references

Structure and physical properties

As shown by X-ray crystallography trirhenium nonachloride consists of Re3Cl12 subunits that share three chloride bridges with adjacent clusters. The interconnected network of clusters forms sheets. Around each Re center are seven ligands, four bridging chlorides, one terminal chloride, and two Re-Re bonds.[2]

Re3Cl12 cluster within ReCl3, shown with full coordination sphere around each chloride.

The heat of oxidation is evaluated according to the equation:

1/3 Re3Cl9 + 4 OH− + 2 OCl− → ReO4− + 2 H2O + 5Cl−

The enthalpy for this process is 190.7 ± 0.2 kcal/mol.[2]

Preparation and reactions

The compound was discovered in 1932, although these workers did not determine its structure, which is unusual for metal chlorides.[3] Trirhenium nonachloride is efficiently prepared by thermal decomposition of rhenium pentachloride or hexachlororhenic(IV) acid:[4]

3 ReCl5 → Re3Cl9 + 3 Cl2

If the sample is vacuum sublimed at 500 °C, the resulting material is comparatively unreactive, but the partially hydrated material can be more useful synthetically. Other synthetic methods include treating rhenium with sulfuryl chloride. This process is sometimes conducted with the addition of aluminium chloride.[2] It is also obtained by heating Re2(O2CCH3)4Cl2 under HCl:

3/2 Re2(O2CCH3)4Cl2 + 6 HCl → Re3Cl9 + 6 HO2CCH3

Reaction of the tri- and pentachlorides gives rhenium tetrachloride:

3 ReCl5 + Re3Cl9 → 6 ReCl4

References
  1. Cotton, F. A.; Walton, R. A. "Multiple Bonds Between Metal Atoms" Oxford (Oxford): 1993. ISBN 0-19-855649-7.
  2. Colton, R. Chemistry of rhenium and technetium. 965.
  3. Geilnann, W.; Wriuce, F. W.; Biltz. W.: Nachr. Ges. Wiss. Gottingen 1932, 579.
  4. Lincoln, R.; Wilkinson, G. (2007). "Trirhenium Nonachloride". Inorganic Syntheses. pp. 44. doi:10.1002/9780470132517.ch12. ISBN 978-0-470-13251-7. {{cite book}}: |journal= ignored (help)
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.