*** Welcome to piglix ***

Rhodium chloride

Rhodium(III) chloride
Rhodium(III) chloride
Rhodium-trichloride-layer-from-xtal-1964-3D-balls.png
Names
Other names
Rhodium trichloride
Identifiers
10049-07-7 YesY
13569-65-8 (trihydrate) YesY[ICSC]
3D model (Jmol) Interactive image
ChemSpider 8096382 YesY
ECHA InfoCard 100.030.138
EC Number 233-165-4
PubChem 24872
RTECS number VI9290000
UNII Q4D88MX3Z8 N
Properties
RhCl3
Molar mass 209.26 g/mol
Appearance dark red solid
deliquescent
Density 5.38 g/cm3, solid
Melting point ca. 450 °C (842 °F; 723 K)
Boiling point 717 °C (1,323 °F; 990 K)
insoluble
Solubility soluble in hydroxide and cyanide solutions, also soluble in aqua regia
Acidity (pKa) acidic in solution
−-7.5·10−6 cm3/mol
Structure
Monoclinic, mS16
C12/m1, No. 12
octahedral
Thermochemistry
−234 kJ/mol
Hazards
Safety data sheet ICSC 0746
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)
>500 mg/kg (rat, oral)
1302 mg/kg (rat, oral)
Related compounds
Other anions
Rhodium(III) fluoride
Rhodium(III) bromide
Rhodium(III) iodide
Other cations
Cobalt(II) chloride
Iridium(III) chloride
Related compounds
Ruthenium(III) chloride
Palladium(II) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of n, the material is either a dense brown solid or a soluble reddish salt. The soluble salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid.

Hydrated rhodium trichloride usually refers to compound with the approximate formula RhCl3(H2O)3.103Rh NMR spectroscopy shows that solutions of this material consist of several species, the proportions of which change with time and depend on the concentration of chloride. The relative distribution of these species determines the colour of the solutions, which can range from yellow (the hexaaquo ion) to "raspberry-red". Some of these species are [Rh(H2O)6]3+, [RhCl(H2O)5]2+, cis- and trans-[RhCl2(H2O)4]+, and [RhCl3(H2O)3]. Individual ions have been separated by ion exchange chromatography.

Anhydrous rhodium chloride crystallises with a monoclinic crystal structure, as in YCl3 and AlCl3. It is a dense brown solid that is insoluble in common solvents and of little value in the laboratory.

RhCl3(H2O)3 is produced from salts such as Na3RhCl6, the latter being obtained in the purification of rhodium from the other platinum group metals such as platinum and iridium. The sodium salt is converted to H3RhCl6 by ion exchange chromatography. Recrystallization of this acidic salt from water affords the hydrated trichloride, sometimes called "soluble rhodium trichloride." Anhydrous RhCl3 is prepared by reaction of chlorine with rhodium sponge metal at 200–300 °C. Above 800 °C, the anhydrous chloride reverts to Rh metal and chlorine.


...
Wikipedia

...