Crystals, black - red with violet shade — plates or needles. It is hygroscopic, blurs on air. tpl =196 °C, with atmospheric pressure decays lower than temperature of boiling. Density is 2,8 g/cm ³; Water solubility — 166 g / 100 (15 °C), 199 g / 100 (100 °C).
CrO3 — acid oxide. At its dissolution in water chromic acid (is formed at lack of CrO3): CrO3 (nedost. ) + H2O → H2CrO4, or dichromic acid (at surplus of CrO3): 2CrO3 + H2O → H2Cr2O7. At interaction of CrO3 with alkalis chromates are formed: CrO3 + 2KOH → K2CrO4 + H2O. When heating above 250 °C decay with formation of chromium oxide (III) and oxygen: 4CrO3 → 2Cr2O3 + 3O2 ↑. As well as all connections Cr (VI), CrO3 is strong oxidizer (it is recovered to Cr2O3). For example ethanol, acetone and many other organic substances self - ignite or even explode at contact with it (though some reference books specify "it is soluble in alcohol and ether"). Oxidizes iod, sulfur, phosphorus, coal, for example: 4CrO3 + 3S → 2Cr2O3 + 3SO2 ↑.
Receive action of H2SO4 on Na2Cr2O7 sodium dichromate (more rare K2Cr2O7 potassium dichromate). Na2Cr2O7 + H2SO4 → 2CrO3 + Na2SO4 + H2O
It is used for receiving chrome by electrolysis, electrolytic chromizing; chromatizings of galvanized details, as strong oxidizer, occasionally in pyrostructures. Apply also as oxidizer in organic chemistry (in production of isatin, indigotin etc. ). In mix with kieselguhr it is applied to purification of acetylene under the name "epurit". Solutions of chromic anhydride (or, more often, potassium dichromate) in sulphuric acid are widely used in laboratory practice for cleaning of ware of organic pollution (cleaning mixture).
Description
Similar company products
Contact the seller
Chrome (VI) oxide