Lithium amide or lithium azanide is an
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
with the chemical formula . It is a white solid with a tetragonal crystal structure. Lithium amide can be made by treating
lithium
Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...
metal with liquid
ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
:
:
Lithium amide decomposes into
ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
and
lithium imide upon heating.
Applications
Lithium amide, when mixed with
lithium hydride, shows applications in
hydrogen storage.
The reaction begins with lithium amide's decomposition into
ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
and
lithium imide. Lithium hydride then
deprotonates ammonia to form lithium amide. The reverse reaction can occur between hydrogen and the lithium imide side product.
Other lithium amides
The conjugate bases of amines are known as amides. Thus, a ''lithium amide'' may also refer to any compound in the class of the lithium salt of an
amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...
. These compounds have the general form , with the chemical lithium amide itself as the
parent structure. Common lithium amides include
lithium diisopropylamide (LDA),
lithium tetramethylpiperidide (LiTMP), and
lithium hexamethyldisilazide (LiHMDS). They are produced by the reaction of Li metal with the appropriate amine:
:
Lithium amides are very reactive compounds. Specifically, they are strong
bases.
Examples
Lithium tetramethylpiperidide has been crystallised as a tetramer. On the other hand, the lithium derivative of bis(1-phenylethyl)amine crystallises as a trimer:
It is also possible to make mixed oligomers of metal
alkoxides and amides.
These are related to the
superbases, which are mixtures of metal alkoxides and alkyls. The cyclic oligomers form when the nitrogen of the amide forms a
sigma bond
In chemistry, sigma bonds (σ bonds) or sigma overlap are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals along the internuclear axis. Sigma bonding is most simply defined for diat ...
to a lithium, while the nitrogen
lone pair
In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bondIUPAC ''Gold Book'' definition''lone (electron) pair''/ref> and is sometimes called an unshared pair or non-bonding pair. Lone ...
binds to another metal centre.
Other organolithium compounds (such as
BuLi) are generally considered to exist in and function via high-order, aggregated species.
See also
*
Sodium amide
*
Potassium amide
*
Butyllithium
*
Lithium imide
*
Lithium nitride
Lithium nitride is an inorganic compound with the chemical formula . It is the only stable alkali metal nitride. It is a reddish-pink solid with a high melting point.
Preparation and handling
Lithium nitride is prepared by direct reaction of ele ...
References
* ''
Merck Index
''The Merck Index'' is an encyclopedia of chemical substance, chemicals, pharmaceutical drug, drugs and biomolecule, biologicals with over 10,000 monographs on single substances or groups of related chemical compound, compounds published online ...
'', 11th Edition, 5398.
External links
{{Lithium compounds
Lithium salts
Metal amides