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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 ...
Chromium(II) ion in aqueous solution. Most aquo complexes are mono-nuclear, with the general formula [M(H 2 O) 6] n+, with n = 2 or 3; they have an octahedral structure. The water molecules function as Lewis bases, donating a pair of electrons to the metal ion and forming a dative covalent bond with it. Typical examples are listed in the ...
Chromium(III) oxide is amphoteric. Although insoluble in water, it reacts with acid to produce salts of hydrated chromium ions such as [Cr(H 2 O) 6] 3+. [11] 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 ...
Chromium also has two metastable nuclear isomers. [9] The primary decay mode before the most abundant stable isotope, 52 Cr, is electron capture and the primary mode after is beta decay. [9] 53 Cr is the radiogenic decay product of 53 Mn (half-life 3.74 million years). [24] Chromium isotopes are typically collocated (and compounded) with ...
In this compound, as in all chromates and dichromates, chromium is in a +6 oxidation state, commonly known as hexavalent chromium. It is a salt consisting of ammonium ions and dichromate ions. Ammonium dichromate is sometimes known as Vesuvian Fire , because of its use in demonstrations of tabletop "volcanoes". [ 2 ]
Chromium trioxide (also known as chromium(VI) oxide or chromic anhydride) is an inorganic compound with the formula CrO 3. 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 ...
Chromium(II) sulfate is an inorganic compound with the chemical formula Cr S O 4. It often comes as hydrates CrSO 4 ·nH 2 O. Several hydrated salts are known. The pentahydrate CrSO 4 ·5H 2 O is a blue solid that dissolves readily in water. Solutions of chromium(II) are easily oxidized by air to Cr(III) species.
Chromium(II) chloride describes inorganic compounds with the formula Cr Cl 2 (H 2 O) n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily dissolves in water to give bright blue air-sensitive solutions of the tetrahydrate Cr(H 2 O) 4 Cl 2 .