Formula Cr(NO3)3 Density 1.85 g/cm³ | Molar mass 238.011 g/mol | |
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Appearance Blue-violet crystals (anhydrous); Purple crystals (nonahydrate) | ||
Chromium nitrate
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. Chromium(III) nitrate compounds are of a limited importance commercially, finding some applications in the dyeing industry. It is common in academic laboratories for the synthesis of chromium coordination complexes.
Contents
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 and preparation
The anhydrous salt forms green crystals and 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.
