Chromium(III) nitrate

Summary

Chromium(III) nitrate describes several inorganic compounds consisting of chromium, nitrate and varying amounts of water. Most common is the dark violet hygrosscopic solid. An anhydrous green form is also known. Chromium(III) nitrate compounds are of a limited commercial importance, finding some applications in the dyeing industry.[2] It is common in academic laboratories for the synthesis of chromium coordination complexes.

Chromium(III) nitrate
Chromium nitrate.svg
Chemical structure of [Cr(H2O)6](NO3)3
Cr(aq)6(NO3)3(aq)3.jpg
Names
IUPAC name
Chromium(III) nitrate
Other names
Nitric acid, chromium(3+) salt
Identifiers
  • 13548-38-4 (anhydrous) checkY
  • 7789-02-8 (nonahydrate) checkY
3D model (JSmol)
  • Interactive image
ChemSpider
  • 15285818 checkY
ECHA InfoCard 100.033.550 Edit this at Wikidata
  • 24598
RTECS number
  • GB6300000
UNII
  • C6H0RE016B (anhydrous) checkY
  • D2806IOL1L (nonahydrate) checkY
UN number 2720
  • DTXSID8065531 Edit this at Wikidata
  • InChI=1S/Cr.3NO3/c;3*2-1(3)4/q+2;3*-1 checkY
    Key: BXWGVGRRIQRLLZ-UHFFFAOYSA-N checkY
  • InChI=1/Cr.3NO3/c;3*2-1(3)4/q+2;3*-1
    Key: BXWGVGRRIQRLLZ-UHFFFAOYAO
  • [Cr+2].O=N([O-])=O.[O-]N(=O)=O.[O-]N(=O)=O
Properties
Cr(NO3)3 (anhydrous)
[Cr(H2O)6](NO3)3•3H2O (nonahydrate)
Molar mass 238.011 g/mol (anhydrous)
400.21 g/mol (nonahydrate)
Appearance Blue-violet crystals (anhydrous)
Purple crystals (nonahydrate)
Density 1.85 g/cm3 (nonahydrate)
Melting point 60.06 °C (140.11 °F; 333.21 K) nonahydrate
Boiling point > 100 °C (212 °F; 373 K) (decomposes)
81 g/100 mL (20 °C)
Hazards
NFPA 704 (fire diamond)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
3250 mg/kg (rat, oral, nonahydrate)
110 mg/kg (mouse, oral)[1]
Safety data sheet (SDS) Oxford MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

StructureEdit

The relatively complicated formula - [Cr(H2O)6](NO3)33H2O - betray a simple structure of this material. The chromium centers are bound to six aquo ligands, and the remaining volume of the solid is occupied by three nitrate anions and three molecules of water of crystallization.[3]

Properties and preparationEdit

The anhydrous salt forms green crystals and is very soluble in water (in contrast to anhydrous chromium(III) chloride which dissolves very slowly except under special conditions). At 100 °C it decomposes. The red-violet hydrate is highly soluble in water. Chromium nitrate is used in the production of alkali metal-free catalysts and in pickling.

Chromium nitrate can be prepared by dissolving chromium oxide in nitric acid.[2]

ReferencesEdit

  1. ^ "Chromium(III) compounds [as Cr(III)]". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  2. ^ a b Anger, Gerd; Halstenberg, Jost; Hochgeschwender, Klaus; Scherhag, Christoph; Korallus, Ulrich; Knopf, Herbert; Schmidt, Peter; Ohlinger, Manfred (2000). "Chromium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a07_067.
  3. ^ Lazar, D.; Ribár, B.; Divjaković, V.; Mészáros, Cs. (1991). "Structure of Hexaaquachromium(III) Nitrate Trihydrate". Acta Crystallographica Section C Crystal Structure Communications. 47 (5): 1060–1062. doi:10.1107/S0108270190012628.