Lithium amide or lithium azanide is an
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the chemical formula . It is a white solid with a tetragonal crystal structure. Lithium amide can be made by treating
lithium metal with liquid
ammonia:
:
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. 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
Lithium bis(trimethylsilyl)amide is a lithiated organosilicon compound with the formula . It is commonly abbreviated as LiHMDS or Li(HMDS) (lithium hexamethyldisilazide - a reference to its conjugate acid HMDS) and is primarily used as a strong ...
(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
alkoxide
In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organic substituent. Alkoxides are strong bases and, whe ...
s 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) are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals. Sigma bonding is most simply defined for diatomic molecules using the language and tools o ...
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. L ...
binds to another metal centre.
Other organolithium compounds (such as
BuLi
Buli may refer to:
* Buli, Halmahera, a town near Maba the capital city of East Halmahera Regency, North Maluku, Indonesia
**Buli Airport, the airport in Buli
**Buli language (Indonesia)
* Buli Rural District, in Iran
*Butyllithium, sometimes abb ...
) are generally considered to exist in and function via high-order, aggregated species.
See also
*
Sodium amide
*
Butyllithium
References
* ''
Merck Index
''The Merck Index'' is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monograph on single substances or groups of related compounds published online by the Royal Society of Chemistry.
History
The first edition of the Mer ...
'', 11th Edition, 5398.
External links
{{Lithium compounds
Lithium salts
Metal amides