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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 .
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).
The Nozaki–Hiyama–Kishi reaction is a nickel/chromium coupling reaction forming an alcohol from the reaction of an aldehyde with an allyl or vinyl halide. [1] In their original 1977 publication, Tamejiro Hiyama and Hitoshi Nozaki [2] reported on a chromium(II) salt solution prepared by reduction of chromic chloride by lithium aluminium hydride to which was added benzaldehyde and allyl ...
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]
Prior to the introduction of this chromium-based protocol, olefination reactions generally gave Z alkenes or mixtures of isomers. [1] Similar olefination reactions had been performed using a variety of reagents such as zinc and lead chloride; [5] however, these olefination reactions often lead to the formation of diols—the McMurry reaction—rather than the methylenation or alkylidenation of ...
It was originally discovered in 1977, where Hiyama and Nozaki reported a chemospecific synthesis of homoallyl alcohols from an aldehyde and allyl halide using chromium(II) chloride. [7] In 1983, Hiyama and Nozaki published another paper extending the scope of the reaction to include aryl and vinyl halides. [8]
He treated phenylmagnesium bromide with chromium(III) chloride to give a new product (after hydrolysis) which he incorrectly identified as pentaphenyl chromium bromide (Ph 5 CrBr). Years later, in 1957 H.H. Zeiss et al. repeated Hein's experiments and correctly arrived at a cationic bisarene chromium sandwich compound (ArH 2 Cr +). [4]
Chromium(II) compounds are uncommon, in part because they readily oxidize to chromium(III) derivatives in air. Water-stable chromium(II) chloride CrCl 2 that can be made by reducing chromium(III) chloride with zinc. The resulting bright blue solution created from dissolving chromium(II) chloride is stable at neutral pH. [21]