Chromium oxide

The Chromium oxide (Cr₂O₃) (also called Chrome green) is the inorganic compound. With the CAS registry number 1308-38-9, its IUPAC name is called oxo(oxochromiooxy)chromium. As one of principal oxides of chromium, Chromium oxide is used as a pigment which was originally called viridian. The chemical belongs to the product categories of Dyes and Pigments; Inorganic & Organic Chemicals; Inorganics. What's more, its EINECS number is 215-160-9. When you are using this chemical, please be cautious about Chromium oxide. You must avoid contacting it with your skin and eyes.

Properties computed from structure of Chromium oxide: (1)H-Bond Donor: 0; (2)H-Bond Acceptor: 3; (3)Rotatable Bond Count: 0; (4)Exact Mass: 151.865768; (5)MonoIsotopic Mass: 151.865768; (6)Topological Polar Surface Area: 43.4; (7)Heavy Atom Count: 5; (8)Formal Charge: 0; (9)Complexity: 34.2; (10)Isotope Atom Count: 0; (11)Defined Atom StereoCenter Count: 0; (12)Undefined Atom StereoCenter Count: 0; (13)Defined Bond StereoCenter Count: 0; (14)Undefined Bond StereoCenter Count: 0; (15)Covalently-Bonded Unit Count: 1.

Properties: Chromium oxide is a hard and brittle material. It turns brown when heated, but reverts to its dark green color when cooled. It is also hygroscopic and is antiferromagnetic up to 307 K, the Neel temperature. It melts at 2435 °C. Chromium oxide is insoluble in water and soluble in acids. It dissolves in acid to produce hydrated chromium ions, [Cr(H₂O)₆]³⁺ and dissolves in concentrated alkali to yield chromite ions. In addition, Chromium oxide is a green crystalline powder.

Preparation: Chromium oxide can be prepared by Na₂Cr₂O₇ reduced with sulfur at high temperatures, by the exothermic decomposition of ammonium dichromate or by the decomposition of chromium salts such as chromium nitrate. The conversion of chromite to chromia proceeds via Na₂Cr₂O₇, according to the following reaction:

Na₂Cr₂O₇ + S → Na₂SO₄ + Cr₂O₃

Uses: Chromium oxide is the colourant in "chrome green" and "institutional green." Chromium oxide is the precursor to the magnetic pigment chromium dioxide, according to the following reaction:

Cr₂O₃ + 3 CrO₃ → 5 CrO₂ + O₂

Structure of Chromium oxide: People can use the following data to convert to the molecule structure.
(1)SMILES: O=[Cr]O[Cr]=O
(2)InChI: InChI=1/2Cr.3O/rCr2O3/c3-1-5-2-4
(3)InChIKey: QDOXWKRWXJOMAK-LUXALHLMAR