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Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH) 3. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids. [2] In alkali: Cr(OH) 3 + OH − → CrO − 2 + 2 H 2 O In acid: Cr(OH) 3 (OH 2) 3 + 3 H + → Cr(OH 2) 6 3+
The Cr 3+ ion has a similar radius (63 pm) to Al 3+ (radius 50 pm), and they can replace each other in some compounds, such as in chrome alum and alum. Chromium(III) tends to form octahedral complexes. Commercially available chromium(III) chloride hydrate is the dark green complex [CrCl 2 (H 2 O) 4]Cl. Closely related compounds are the pale ...
In acid solution the aquated Cr 3+ ion is produced. Cr 2 O 2− 7 + 14 H + + 6 e − → 2 Cr 3+ + 7 H 2 O ε 0 = 1.33 V. In alkaline solution chromium(III) hydroxide is produced. The redox potential shows that chromates are weaker oxidizing agent in alkaline solution than in acid solution. [6] CrO 2− 4 + 4 H 2 O + 3 e − → Cr(OH) 3 + 5 OH −
Calcium carbonate (Precipitated Chalk) – CaCO 3; Calcium chlorate – Ca(ClO 3) 2; Calcium chloride – CaCl 2; Calcium chromate – CaCrO 4; Calcium cyanamide – CaCN 2; Calcium fluoride – CaF 2; Calcium hydride – CaH 2; Calcium hydroxide – Ca(OH) 2; Calcium monosilicide – CaSi; Calcium oxalate – CaC 2 O 4; Calcium hydroxychloride ...
4 + Cr 2 O 3. The oxide is also formed by the decomposition of chromium salts such as chromium nitrate, or by the exothermic decomposition of ammonium dichromate. (NH 4) 2 Cr 2 O 7 → Cr 2 O 3 + N 2 + 4 H 2 O. The reaction has a low ignition temperature of less than 200 °C and is frequently used in “volcano” demonstrations. [8]
Chromium trioxide decomposes above 197 °C, liberating oxygen and eventually giving Cr 2 O 3: 4 CrO 3 → 2 Cr 2 O 3 + 3 O 2. It is used in organic synthesis as an oxidant, often as a solution in acetic acid, [9] or acetone in the case of the Jones oxidation. In these oxidations, the Cr(VI) converts primary alcohols to the corresponding ...
Chromium(III) chloride (also called chromic chloride) is an inorganic chemical compound with the chemical formula Cr Cl 3.It forms several hydrates with the formula CrCl 3 ·nH 2 O, among which are hydrates where n can be 5 (chromium(III) chloride pentahydrate CrCl 3 ·5H 2 O) or 6 (chromium(III) chloride hexahydrate CrCl 3 ·6H 2 O).
3, form when oxygen combines with other elements. Due to its electronegativity, oxygen forms chemical bonds with almost all other free elements at elevated temperatures to give corresponding oxides. However, some elements, such as iron which oxidises to iron oxide, or rust, Fe 2 O 3, readily oxidise at standard conditions for temperature and ...