Search results
Results from the WOW.Com Content Network
It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. [6] This compound is a dark-purple solid under anhydrous conditions and bright orange when wet. The substance dissolves in water accompanied by hydrolysis. [clarification needed] Millions of kilograms are produced annually, mainly for electroplating. [7]
At yet lower pH values, further condensation to more complex oxyanions of chromium is possible. Both the chromate and dichromate anions are strong oxidizing reagents at low pH: [6] Cr 2 O 2− 7 + 14 H 3 O + + 6 e − → 2 Cr 3+ + 21 H 2 O (ε 0 = 1.33 V) They are, however, only moderately oxidizing at high pH: [6] CrO 2− 4 + 4 H 2 O + 3 e ...
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−
This kind of chromic acid may be used as a cleaning mixture for glass. Chromic acid may also refer to the molecular species, H 2 CrO 4 of which the trioxide is the anhydride. Chromic acid features chromium in an oxidation state of +6 (and a valence of VI or 6). It is a strong and corrosive oxidizing agent and a moderate carcinogen.
Although insoluble in water, it reacts with acid to produce salts of hydrated chromium ions such as [Cr(H 2 O) 6] 3+. [10] It is also attacked by concentrated alkali to yield salts of [Cr(OH) 6] 3−. When heated with finely divided carbon or aluminium, it is reduced to chromium metal: Cr 2 O 3 + 2 Al → 2 Cr + Al 2 O 3
It is readily oxidized by the atmosphere. CrO is basic, while CrO 3 is acidic, and Cr 2 O 3 is amphoteric. [3] CrO occurs in the spectra of luminous red novae, which occur when two stars collide. It is not known why red novae are the only objects that feature this molecule; one possible explanation is an as-yet-unknown nucleosynthesis process. [4]
Basic state minimums often fall short in real-world accidents, and you may be personally responsible for paying the difference from your own assets. 2. Collision coverage.
Structure of CrO(O 2) 2 (pyridine).Hydrogen atoms bonded to carbon atoms are omitted. Color code: Cr = gray, C= black, H = white, O= red, N = blue. Chromium(VI) oxide peroxide is formed by the addition of acidified hydrogen peroxide solutions to solutions of metal chromates or dichromates, such as sodium chromate or potassium dichromate.