Chromium nitrate

Chromium nitrate
IUPAC name Chromium(III) nitrate
Other names Nitric acid, chromium(3+) salt
Identifiers
CAS number	13548-38-4 Y, 7789-02-8 (nonahydrate) Y
PubChem	24598
ChemSpider	15285818 Y
UNII	C6H0RE016B Y
UN number	2720
RTECS number	GB6300000
Jmol-3D images	Image 1
SMILES [Cr+2].O=N([O-])=O.[O-]N(=O)=O.[O-]N(=O)=O
InChI InChI=1S/Cr.3NO3/c;3*2-1(3)4/q+2;3*-1 Y Key: BXWGVGRRIQRLLZ-UHFFFAOYSA-N Y InChI=1/Cr.3NO3/c;3*2-1(3)4/q+2;3*-1 Key: BXWGVGRRIQRLLZ-UHFFFAOYAO
Properties
Molecular formula	Cr(NO3)3 [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, 333 K, 140 °F (nonahydrate)
Boiling point	> 100 °C (212 °F) (decomp.)
Solubility in water	81 g/100 mL (20 °C)
Hazards
MSDS	Oxford MSDS
EU Index	Not listed
NFPA 704	0 3 1 OX
Flash point	Non flammable
LD50	3250 mg/kg (rat, oral, nonahydrate)
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Chromium(III) nitrate describes several inorganic compounds consisting of chromium, nitrate and varying amounts of water. Most common is the dark violet hydrated solid, but an anhydrous green form is also known. These compounds are not important commercially but are commonly found in academic laboratories.

Structure

The relatively complicated formula - [Cr(H₂O)₆](NO₃)₃•3H₂O - highlights the complicated structure of this material. The chromium centers are bound to six water ligands, and the remaining volume of the solid is occupied by three nitrate anions and three molecules of water of crystallization. Such complicated formulas typify hydrated metal salts.

Properties

The anhydrous salt forms green crystals and very soluble in water. 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.

Preparation

Chromium nitrate can be prepared by dissolving chromium oxide in nitric acid.^[1]

References

1. ^ Gerd Anger, Jost Halstenberg, Klaus Hochgeschwender, Christoph Scherhag, Ulrich Korallus, Herbert Knopf, Peter Schmidt, Manfred Ohlinger, "Chromium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.