Rhodium (III) oxide

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Crystal structure
Structure of rhodium (III) oxide
__ Rh 3+      __ O 2−
General
Surname Rhodium (III) oxide
other names

Dirhodium trioxide

Ratio formula Rh 2 O 3
Brief description

gray-black odorless solid

External identifiers / databases
CAS number 12036-35-0
EC number 234-846-9
ECHA InfoCard 100,031,666
PubChem 159409
Wikidata Q3488660
properties
Molar mass 253.81 g mol −1
Physical state

firmly

density

8.20 g cm −3

Melting point

1100 ° C (decomposition)

solubility

almost insoluble in water

safety instructions
GHS labeling of hazardous substances
no GHS pictograms
H and P phrases H: no H-phrases
P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Rhodium (III) oxide is an inorganic chemical compound of rhodium from the group of oxides .

Extraction and presentation

Rhodium (III) oxide can be obtained by reacting anhydrous rhodium (III) salts such as rhodium (III) chloride with oxygen at 750–800 ° C. It can also be obtained directly from the elements. The rhodium (III) oxide hydrate can be obtained by precipitating an aqueous sodium hexachlororhodate or potassium hexachlororhodate solution with sodium or potassium hydroxide solution.

properties

Rhodium (III) oxide is a paramagnetic black-gray odorless solid that is neither soluble in water nor in acids. It has a crystal structure isotypic to that of aluminum (III) oxide (corundum) with the space group R 3 c (space group no. 167) and the lattice parameters a = 547 pm and α = 55 ° 40 '. At 750 ° C this changes into an orthorhombic form. Its pentahydrate (rhodium oxide hydrate) is a pale yellow powder that is insoluble in water and soluble in acids. Reaction with nitric acid leads to rhodium (III) nitrate . Template: room group / 167

Individual evidence

  1. a b c d e f g Data sheet Rhodium (III) oxide, anhydrous, 99.9% (metals basis), Rh 80.6% min from AlfaAesar, accessed on September 1, 2013 ( PDF )(JavaScript required) .
  2. ^ A b Aaron Wold, Kirby Dwight: Solid State Chemistry: Synthesis, Structure, and Properties of Selected ... Springer, 1993, ISBN 0-412-03621-5 , pp. 119 ( limited preview in Google Book search).
  3. a b Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1634.
  4. JMD Coey: The crystal structure of Rh2O3. In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 26, pp. 1876-1877, doi : 10.1107 / S0567740870005022 .