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The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [1] [2] 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 ...
The chromium(II) hydride monomer, is both thermodynamically and kinetically unstable towards autopolymerization at ambient temperature, and so cannot be concentrated. Nevertheless, molecules of CrH 2 and Cr 2 H 4 have been isolated in solid gas matrices. [1] Cr is the second simplest molecular chromium hydride (after Chromium(I) hydride).
Predominance diagram for chromate. In aqueous solution, chromate and dichromate anions exist in a chemical equilibrium.. 2 CrO 2− 4 + 2 H + ⇌ Cr 2 O 2− 7 + H 2 O. The predominance diagram shows that the position of the equilibrium depends on both pH and the analytical concentration of chromium.
It can occur as a dull brown or dark grey solid in two different crystalline forms: face-centered cubic with formula CrH ~2 or a close packed hexagonal solid with formula CrH ~1. Chromium hydride is important in chrome plating, being an intermediate in the formation of the chromium plate.
Molecular weight (M.W.) (for molecular compounds) and formula weight (F.W.) (for non-molecular compounds), are older terms for what is now more correctly called the relative molar mass (M r). [8] This is a dimensionless quantity (i.e., a pure number, without units) equal to the molar mass divided by the molar mass constant .
The resulting bright blue solution created from dissolving chromium(II) chloride is stable at neutral pH. [21] Some other notable chromium(II) compounds include chromium(II) oxide CrO, and chromium(II) sulfate CrSO 4. Many chromium(II) carboxylates are known. The red chromium(II) acetate (Cr 2 (O 2 CCH 3) 4) is somewhat famous. It features a Cr ...
Loss of the second proton occurs in the pH range 4–8, making the ion [HCrO 4] − a weak acid. [citation needed] Molecular chromic acid could in principle be made by adding chromium trioxide to water (cf. manufacture of sulfuric acid). CrO 3 + H 2 O ⇌ H 2 CrO 4. In practice, the reverse reaction occurs: molecular chromic acid dehydrates ...
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+