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Zinc compounds, like those of main group elements, are mostly colourless. Exceptions occur when the compound contains a coloured anion or ligand. However, zinc selenide and zinc telluride are both coloured due to charge-transfer processes. Zinc oxide turns yellow when heated due to the loss of some oxygen atoms and formation of a defect structure
The Charette modification replaces the CH 2 I 2 normally found in the Simmons–Smith reaction with aryldiazo compounds, such as phenyldiazomethane, in Pathway A. [30] Upon treatment with stoichiometric amounts of zinc halide, an organozinc compound similar to the carbenoid discussed above is produced. This can react with almost all alkenes and ...
The reaction is effected with zinc. The key zinc-intermediate formed is a carbenoid (iodomethyl)zinc iodide which reacts with alkenes to afford the cyclopropanated product. The rate of forming the active zinc species is increased via ultrasonication since the initial reaction occurs at the surface of the metal.
Organozincs are moisture and air sensitive, so the Negishi coupling must be performed in an oxygen and water free environment, a fact that has hindered its use relative to other cross-coupling reactions that require less robust conditions (i.e. Suzuki reaction). However, organozincs are more reactive than both organostannanes and organoborates ...
Zinc powder is sometimes used as a propellant in model rockets. [152] When a compressed mixture of 70% zinc and 30% sulfur powder is ignited there is a violent chemical reaction. [152] This produces zinc sulfide, together with large amounts of hot gas, heat, and light. [152]
For instance, zinc and cadmium are similar to beryllium and magnesium in their atomic radii, ionic radii, electronegativities, and also in the structure of their binary compounds and their ability to form complex ions with many nitrogen and oxygen ligands, such as complex hydrides and amines.
The oxygen on an aldehyde or ketone coordinates to the zinc to form the six-member chair like transition state 3. A rearrangement occurs in which zinc switches to the aldehyde or ketone oxygen and a carbon-carbon bond is formed 4. Acid workup 5,6 removes zinc to yield zinc(II) salts and a β-hydroxy-ester 7. [5]
The by-product of the reaction is ammonia. [4] 3 Zn(NH 2) 2 → Zn 3 N 2 + 4 NH 3. It can also be formed by heating zinc to 600 °C in a current of ammonia; the by-product is hydrogen gas. [3] [5] 3 Zn + 2 NH 3 → Zn 3 N 2 + 3 H 2. The decomposition of Zinc Nitride into the elements at the same temperature is a competing reaction. [6] At 700 ...