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Further condensation reactions can occur in strongly acidic solution with the formation of trichromates, Cr 3 O 2− 10, and tetrachromates, Cr 4 O 2− 13. [2] All polyoxyanions of chromium(VI) have structures made up of tetrahedral CrO 4 units sharing corners. [3] The hydrogen chromate ion, HCrO 4 −, is a weak acid: HCrO − 4 ⇌ CrO 2−
Names IUPAC name. iron(III) chromate. ... 4 Fe 2 O 3 + 6 Cr 2 O 3 + 9 O 2 → 4 Fe 2 (CrO 4) 3. References This page was last edited on 30 August 2022, at 14:00 ...
Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals . The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist.
Chromium(III) oxide, Cr 2 O 3; Chromium dioxide (chromium(IV) oxide), CrO 2, which includes the hypothetical compound chromium(II) chromate; Chromium trioxide (chromium(VI) oxide), CrO 3; Chromium(VI) oxide peroxide, CrO 5; Mixed valence species, such as Cr 8 O 21
The Parisians Pannetier and Binet first prepared the transparent hydrated form of Cr 2 O 3 in 1838 via a secret process, sold as a pigment. [6] It is derived from the mineral chromite, (Fe,Mg)Cr 2 O 4. The conversion of chromite to chromia proceeds via Na 2 Cr 2 O 7, which is reduced with sulfur at high temperatures: [7] Na 2 Cr 2 O 7 + S → ...
2Cr 2 O 3 + 4 Na 2 CO 3 + 3 O 2 → 4 Na 2 CrO 4 + 4 CO 2. This process converts the chromium into a water-extractable form, leaving behind iron oxides. Typically calcium carbonate is included in the mixture to improve oxygen access and to keep silicon and aluminium impurities in an insoluble form. The process temperature is typically around ...
Other compounds with the general formula Cr(ClO 4) 3 (NH 3) x are also known. When x = 3, this compound is red, when x = 4 or 5, it is orange. [5] The hexammine complex will explode. [5] Cr(ClO 4) 3 can also form complexes with N 2 H 4, such as purple Cr(ClO 4) 3 ·2N 2 H 4. [6]
[3] Aqueous chromium(VI) oxide peroxide decomposes in a few seconds, turning green as chromium(III) compounds are formed. [4] 2 CrO(O 2) 2 + 7 H 2 O 2 + 6 H + → 2 Cr 3+ + 10 H 2 O + 7 O 2. Stable adducts of the type CrO(O 2) 2 L include those with L = diethyl ether, 1-butanol, ethyl acetate, or amyl acetate. They form by adding a layer of the ...