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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. [3] [4]
Heating a solution of Cr(CO) 6 in an aromatic solvent results in replacement of three CO ligands. The reactions are especially favorable for electron-rich arenes: Cr(CO) 6 + C 6 H 5 R → Cr(CO) 3 (C 6 H 5 R) + 3 CO. The products are "piano stool complexes". These species are typically yellow solids. One example is (benzene)chromium tricarbonyl.
The organochromium compound (phenylmethoxycarbene)pentacarbonylchromium, Ph(OCH 3)C=Cr(CO) 5 was the first carbene complex to be crystallographically characterized by Fischer in 1967 (now called a Fischer carbene). [14] The first ever carbyne, this one also containing chromium, made its debut in 1973. [15]
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 ...
6 carbon: C −4: −3: ... The oxidation states are also ... bt bu bv bw bx by bz ca cb cc cd ce cf cg ch ci cj ck cl cm cn co cp cq cr cs ct cu cv cw cx cy cz da db ...
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 ...
8, has been described as having a carbon oxidation state of − 8 / 3 . [19] Again, this is an average value since the structure of the molecule is H 3 C−CH 2 −CH 3, with the first and third carbon atoms each having an oxidation state of −3 and the central one −2.
A chromate ester is a chemical structure that contains a chromium atom (symbol Cr) in a +6 oxidation state that is connected via an oxygen (O) linkage to a carbon (C) atom. The Cr itself is in its chromate form, with several oxygens attached, and the Cr–O–C attachment makes this chemical group structurally similar to other ester functional groups.