Zinc hydride
Encyclopedia
Zinc hydride is a chemical compound of zinc
and hydrogen
, ZnH2, which is used as a reducing agent
in organic synthesis. First reported in 1947, it is a white crystalline powder when freshly made which turns grey if left at room temperature for a few days, presumably due to the decompostion to metallic zinc. It can be prepared in a number of ways:
It decomposes at 90 °C into the elements. It is sensitive to air and moisture, and is hydrolysed slowly by water but violently by aqueous acids. Older samples may be pyrophoric.
The solid state structure is not known but is believed to involve covalent bonding
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, ZnH2, which is used as a reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
in organic synthesis. First reported in 1947, it is a white crystalline powder when freshly made which turns grey if left at room temperature for a few days, presumably due to the decompostion to metallic zinc. It can be prepared in a number of ways:
- 2LiHLithium hydrideLithium hydride is the inorganic compound with the formula LiH. It is a colorless solid, although commercial samples are gray. Characteristic of a salt-like, or ionic, hydride, it has a high melting point and is not soluble in any solvent with which it does not react...
+ ZnBr2Zinc bromideZinc bromide is a inorganic compound with the chemical formula ZnBr2. It is a colourless salt that shares many properties with zinc chloride , namely a high solubility in water forming acidic solutions, and solubility in organic solvents...
→ ZnH2 + 2LiBrLithium bromideLithium bromide, or LiBr, is a chemical compound of lithium and bromine. Its extreme hygroscopic character makes LiBr useful as a desiccant in certain air conditioning systems.-Production and properties:... - 2NaHSodium hydrideSodium hydride is the chemical compound with the empirical formula NaH. It is primarily used as a strong base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na+ and H− ions, in contrast to the more molecular hydrides such as...
+ ZnI2Zinc iodideZinc iodide is a chemical compound of zinc and iodine, ZnI2. The anhydrous form is white and readily absorbs water from the atmosphere. It can be prepared by the direct reaction of zinc and iodine in refluxing ether...
→ ZnH2 + 2NaISodium iodideSodium iodide is a white, crystalline salt with chemical formula NaI used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.-Uses:Sodium iodide is commonly used to treat and prevent iodine deficiency.... - ZnI2Zinc iodideZinc iodide is a chemical compound of zinc and iodine, ZnI2. The anhydrous form is white and readily absorbs water from the atmosphere. It can be prepared by the direct reaction of zinc and iodine in refluxing ether...
+ 2LiAlH4Lithium aluminium hydrideLithium aluminium hydride, commonly abbreviated to LAH or known as LithAl, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters,...
→ ZnH2 + AlH3Aluminium hydrideAluminium hydride is an inorganic compound with the formula AlH3. It is a colourless solid that is pyrophoric. Although rarely encountered outside of research laboratory, alane and its derivatives are used as reducing agents in organic synthesis.-Structure:...
+ 2LiILithium iodideLithium iodide, or LiI, is a compound of lithium and iodine. When exposed to air, it becomes yellow in color, due to the oxidation of iodide to iodine.-Applications:... - Zn(CH3)2DimethylzincDimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless mobile liquid Zn2, formed by the action of methyl iodide on zinc at elevated temperature or on zinc sodium alloy....
+ LiAlH4Lithium aluminium hydrideLithium aluminium hydride, commonly abbreviated to LAH or known as LithAl, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters,...
→ ZnH2 + LiAlH3(CH3)
It decomposes at 90 °C into the elements. It is sensitive to air and moisture, and is hydrolysed slowly by water but violently by aqueous acids. Older samples may be pyrophoric.
The solid state structure is not known but is believed to involve covalent bonding