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Some metal hydrides form when a metal complex is treated with hydrogen in the presence of a base. The reaction involves no changes in the oxidation state of the metal and can be viewed as splitting H 2 into hydride (which binds to the metal) and proton (which binds to the base). ML n x+ + base + H 2 ⇌ HML n (x-1)+ + Hbase +
Classical transition metal hydride feature a single bond between the hydrogen centre and the transition metal. Some transition metal hydrides are acidic, e.g., HCo(CO) 4 and H 2 Fe(CO) 4. The anions potassium nonahydridorhenate [ReH 9] 2− and [FeH 6] 4− are examples from the growing collection of known molecular homoleptic metal hydrides. [16]
In general, complex metal hydrides have the formula M x M' y H n, where M is an alkali metal cation or cation complex and M' is a metal or metalloid.Well known examples feature group 13 elements, especially boron and aluminium including sodium aluminium hydride, NaAlH 4), lithium aluminium hydride, LiAlH 4, and lithium borohydride, (LiBH 4).
Proposed hydrides for use in a hydrogen economy include simple hydrides of magnesium [19] or transition metals and complex metal hydrides, typically containing sodium, lithium, or calcium and aluminium or boron. Hydrides chosen for storage applications provide low reactivity (high safety) and high hydrogen storage densities.
The neutral metal carbonyl hydrides are often volatile and can be quite acidic. [5] The hydrogen atom is directly bounded to the metal. The metal-hydrogen bond length is for cobalt 114 pm, the metal-carbon bond length is for axial ligands 176 and 182 for the equatorial ligands. [6] A direct metal-hydrogen bond was suspected by Hieber for H 2 Fe ...
Borderline hydrides typically refer to hydrides formed of hydrogen and elements of the periodic table in group 11 and group 12 and indium (In) and thallium (Tl). [citation needed] These compounds have properties intermediate between covalent hydrides and saline hydrides. Hydrides are chemical compounds that contain a metal and hydrogen acting ...
Most examples are cationic transition metals complexes with octahedral geometry. Upon complexation, the H−H bond is extended to 0.81–0.82 Å as indicated by neutron diffraction, about a 10% extension relative to the H−H bond in free H 2. Some complexes containing multiple hydrogen ligands, i.e. polyhydrides, also exhibit short H−H contacts.
A hydride compressor is a hydrogen compressor based on metal hydrides with absorption of hydrogen at low pressure, releasing heat, and desorption of hydrogen at high pressure, absorbing heat, by raising the temperature with an external heat source like a heated waterbed or electric coil.