The inorganic imide is an

inorganic 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''. Inor ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

containing *an

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

, in which

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

atom is

covalently A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms ...

bonded to one

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

atom (as in

lithium imide Lithium imide is an inorganic compound with the chemical formula . This white solid can be formed by a reaction between lithium amide and lithium hydride. : The product is light-sensitive and can undergo disproportionation to lithium amide and c ...

and calcium imide ). The other name of that anion is monohydrogen nitride. *

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s with the chemical formulas or , in which nitrogen atom is also covalently bonded to one hydrogen atom, with two covalent

single bond In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond. When shared, each of th ...

s or one covalent

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...

from the nitrogen atom to other atoms, respectively (as in heptasulfur imide ,

sulfur diimide Sulfur diimides are chemical compounds of the formula S(NR)2. Structurally, they are the diimine of sulfur dioxide. The parent member, S(NH)2, is of only theoretical interest. Other derivatives where R is an organic group are stable and useful rea ...

and

nitroxyl Nitroxyl (common name) or azanone (IUPAC name) is the chemical compound HNO. It is well known in the gas phase. Nitroxyl can be formed as a short-lived intermediate in solution. Its conjugate base, NO−, the nitroxide anion, is the reduced form o ...

). Organic imides have the functional groups or as well. The imides are related to the inorganic amides, containing the anions, the

nitride In chemistry, a nitride is a chemical compound of nitrogen. Nitrides can be inorganic or organic, ionic or covalent. The nitride anion, N3−, is very elusive but compounds of nitride are numerous, although rarely naturally occurring. Some nitr ...

s, containing the anions and the nitridohydrides or nitride hydrides, containing both nitride and

hydride In chemistry, a hydride is formally the anion of hydrogen (H−), a hydrogen ion with two electrons. In modern usage, this is typically only used for ionic bonds, but it is sometimes (and has been more frequently in the past) applied to all che ...

anions. In addition to solid state imides, molecular imides are also known in dilute gases, where their spectrum can be studied. When covalently bound to a metal, an imide

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

produces a

transition metal imido complex In coordination chemistry and organometallic chemistry, transition metal imido complexes is a coordination compound containing an imido ligand. Imido ligands can be terminal or bridging ligands. The parent imido ligand has the formula NH, but most ...

. When the hydrogen of the imide group is substituted by an organic group, an organoimide results. Complexes of

actinide The actinide () or actinoid () series encompasses at least the 14 metallic chemical elements in the 5f series, with atomic numbers from 89 to 102, actinium through nobelium. Number 103, lawrencium, is also generally included despite being part ...

and

rare earth element The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set o ...

s with organoimides are known.

Properties

Lithium imide Lithium imide is an inorganic compound with the chemical formula . This white solid can be formed by a reaction between lithium amide and lithium hydride. : The product is light-sensitive and can undergo disproportionation to lithium amide and c ...

undergoes a phase transition at 87 °C where it goes from an ordered to a more symmetric disordered state.

Structure

Many imides have a cubic rock salt structure, with the metal and nitrogen occupying the main positions. The position of the hydrogen atom is hard to determine, but is disordered. Many of the heavy metal simple imide molecules are linear. This is due to the filled 2p orbital of nitrogen donating electrons to an empty d orbital on the metal.

Imides in coordination chemistry

coordination chemistry A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

es feature the NR^2- ligand. They are similar to oxo ligands in some respects. In some the M-N-C angle is 180º but often the angle is decidedly bent. The parent imide (NH^2-) is an intermediate in

nitrogen fixation Nitrogen fixation is a chemical process by which molecular dinitrogen () is converted into ammonia (). It occurs both biologically and abiological nitrogen fixation, abiologically in chemical industry, chemical industries. Biological nitrogen ...

by synthetic catalysts. TiImide

Formation

Heating

lithium amide Lithium amide or lithium azanide is an inorganic compound 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: : Lithium amide decomposes into ...

with

lithium hydride Lithium hydride is an inorganic compound with the formula Li H. This alkali metal hydride is a colorless solid, although commercial samples are grey. Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not solub ...

yields lithium imide and hydrogen gas. This reaction takes place as released

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 ...

reacts with lithium hydride. Heating magnesium amide to about 400 °C yields magnesium imide with the loss of

. Magnesium imide itself decomposes if heated between 455 and 490 °C. Beryllium imide forms from beryllium amide when heated to 230 °C in a vacuum. When strontium metal is heated with ammonia at 750 °C, the dark yellow strontium imide forms. When barium vapour is heated with ammonia in an electrical discharge, the gaseous, molecular BaNH is formed. Molecules ScNH, YNH, and LaNH are also known.

Hydrogen storage

Inorganic imides are of interest because they can reversibly store hydrogen, which may be important for the

hydrogen economy The hydrogen economy is an umbrella term for the roles hydrogen can play alongside low-carbon electricity to reduce emissions of greenhouse gases. The aim is to reduce emissions where cheaper and more energy-efficient clean solutions are not ava ...

. For example, calcium imide can store 2.1% mass of hydrogen. reversibly stores hydrogen and release it at temperatures between 140 and 206 °C. It can reversibly hold 2.3% hydrogen. When hydrogen is added to the imide, amides and hydrides are produced. When imides are heated, they can yield hydridonitrides or nitrides, but these may not easily reabsorb hydrogen.

List

Ionic

Molecular

Molecular imines of other actinides called neptunimine and plutonimine have been postulated to exist in the gas phase or noble gas matrix.

References

{{Reflist Nitrogen compounds Hydrogen compounds