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Trirhenium nonachloride

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Trirhenium nonachloride
Names
IUPAC name
Rhenium(III) chloride
Other names
Rhenium trichloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.033.610 Edit this at Wikidata
EC Number
  • 236-987-1
  • InChI=1S/3ClH.Re/h3*1H;/q;;;+3/p-3
  • ReCl3: Cl[Re](Cl)Cl
  • Re3Cl9: Cl[Re-]12(Cl)([Cl+]3)[Re-]3(Cl)(Cl)([Cl+]4)[Re-]14(Cl)(Cl)([Cl+]2)
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).
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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.

Structure and physical properties

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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 hydrate is molecular with the formula Re3Cl9(H2O)3.[3]

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

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The compound was discovered in 1932.[4] Trirhenium nonachloride is efficiently prepared by thermal decomposition of rhenium pentachloride or hexachlororhenic(IV) acid:[5]

3 ReCl5 → Re3Cl9 + 3 Cl2

If the sample is vacuum sublimed at 500 °C, the resulting material is comparatively unreactive. The partially hydrated material such as Re3Cl9(H2O)4[6] 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

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  1. ^ Cotton, F. A.; Walton, R. A. "Multiple Bonds Between Metal Atoms" Oxford (Oxford): 1993. ISBN 0-19-855649-7.
  2. ^ a b c Colton, R. Chemistry of rhenium and technetium. 965.
  3. ^ Irmler, Manfred; Meyer, Gerd (1987). "Rhenium trichloride, ReCl3, and its 5/3-hydrate synthesis, crystal structure, and thermal expansion". Zeitschrift für Anorganische und Allgemeine Chemie. 552 (9): 81–89. doi:10.1002/zaac.19875520908.
  4. ^ Geilnann, W.; Wriuce, F. W.; Biltz. W.: Nachr. Ges. Wiss. Gottingen 1932, 579.
  5. ^ Lincoln, R.; Wilkinson, G. (1980). "Trirhenium Nonachloride". Inorg. Synth. 20: 44. doi:10.1002/9780470132517.ch12. ISBN 978-0-470-13251-7.
  6. ^ Irmler, Manfred; Meyer, Gerd (1987). "Rhenium trichloride, ReCl3, and its 5/3-hydrate synthesis, crystal structure, and thermal expansion". Zeitschrift für Anorganische und Allgemeine Chemie. 552 (9): 81–89. doi:10.1002/zaac.19875520908.