CHROMIUM(III) NITRATE NONAHYDRATE

Chemical properties

deep blue or violet crystals

Chemical properties

Chromium nitrate is a crystalline substance, variously stated to be green brown or purple and existing in various hydrated forms.

The Uses of CHROMIUM(III) NITRATE NONAHYDRATE

Chromium nitrate is used in the manufacture of alkali metal-free catalysts and in preservation. It is used in the preparation of chrome catalysts, in textile printing operations, and as a corrosion inhibitor. Chromium(III) nitrate as a source of chromium is added to food supplements for nutritional purposes .

Potential Exposure

Chromium nitrate is used in the preparation of chrome catalysts, in textile printing operations; and as a corrosion inhibitor. Used to make other chemicals.

Shipping

UN2720 Chromium nitrate, Hazard Class: 5.1; Labels: 5.1-Oxidizer

Purification Methods

The pure deep violet nonahydrate salt is best prepared freshly from pure recrystallised (3 times) chromium (VI) trioxide and pure nitric acid. A solution is prepared by dissolving 1g of CrO3 in 3mL of H2O and 2mL of pure HNO3, and carefully, with stirring (behind a screen) pure MeOH (0.5-1.0mL) is added dropwise carefully (shield) with cooling to avoid a violent reaction. A bluish colour develops as Cr(VI) is reduced to Cr(III). When this solution is diluted to 130,000ppm of the salt, analysis detected by ICP/MS gave the following trace elements (ppm in brackets): Sr (33), Na (3.5), Mo, Ni, Cu, Si and Mg (0.13 each), Se, Zn, Al (0.026 each), Ti (1.5), Fe (4.9), Co (0.07), Sn (0.065), Ba (0.013 and W (0.078). Evaporation of the methanolic solution in high vacuum over CaCl2 eventually yields pure deep violet rhombic crystals of chromium (III) nitrate nonahydrate. An aqueous solution of this salt becomes green on heating but reverts to the violet colour on cooling.

Incompatibilities

This chemical is a strong oxidizer. Contact with reducing agents; fuels, ethers, and other flammable and combustible materials cause a fire and explosion hazard. Violent reaction with many compounds, including reducing agents; alcohols, chemically active metals; combustible materials, strong acids, alkaline earth sulfides, aluminum carbides, aluminum, amines, calcium sulfide, carbides, chlorine trifluoride, glycerin, hydrides, hydrochloric acid, hydrogen peroxide, hydrogen sulfide, hydroxylamine, magnesium, metal powders, metal sulfides, molybdenum, phenylhydrazine, phosphorous red/friction, phosphorous trichloride, silicon, sulfides, sulfur, sulfur Chromium Nitrate 845 dioxide, sulfur/friction, sulfuric acid, tungsten, hydrogen trisulfide

Waste Disposal

Precipitate chromium as the hydroxide. Dewater the sludge and dispose of in singlepurpose dumps.