Azanes are acyclic,

saturated Saturation, saturated, unsaturation or unsaturated may refer to: Chemistry * Saturation, a property of organic compounds referring to carbon-carbon bonds ** Saturated and unsaturated compounds **Degree of unsaturation ** Saturated fat or fatty ac ...

hydronitrogens, which means that they consist only of

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

and

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

atoms and all bonds are single bonds. They are therefore

pnictogen hydride Pnictogen hydrides or hydrogen pnictides are binary compounds of hydrogen with pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") atoms (elements of group 15: nitrogen, phosphorus, arsenic, antimony, and bismuth) covalently ...

s. Because

cyclic Cycle, cycles, or cyclic may refer to: Anthropology and social sciences * Cyclic history, a theory of history * Cyclical theory, a theory of American political history associated with Arthur Schlesinger, Sr. * Social cycle, various cycles in s ...

hydronitrogens are excluded by definition, the azanes comprise a homologous series of inorganic compounds with the general chemical formula . Each nitrogen atom has three bonds (either N-H or N-N bonds), and each hydrogen atom is joined to a nitrogen atom (H-N bonds). A series of linked nitrogen atoms is known as the nitrogen skeleton or nitrogen backbone. The number of nitrogen atoms is used to define the size of the azane (e.g. N₂-azane). The simplest possible azane (the parent molecule) is

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

, . There is no limit to the number of nitrogen atoms that can be linked together, the only limitation being that the molecule is acyclic, is saturated, and is a hydronitrogen. Azanes are reactive and have significant biological activity. Azanes can be viewed as a more biologically active or reactive portion (

functional groups In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...

) of the molecule, which can be hung upon molecular trees.

Structure classification

Saturated hydronitrogens can be: *linear (general formula ) wherein the nitrogen atoms are joined in a snakelike structure *branched (general formula , ''n'' > 3) wherein the nitrogen backbone splits off in one or more directions *

(general formula , ''n'' > 2) wherein the nitrogen backbone is linked so as to form a loop. According to

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

definitions, the former two are azanes, whereas the third group is called cycloazanes. Saturated hydronitrogens can also combine any of the linear, cyclic (e.g. polycyclic), and branching structures, and they are still azanes (no general formula) as long as they are acyclic (i.e., having no loops). They also have single covalent bonds between their nitrogens.

Isomerism

Azanes with more than three nitrogen atoms can be arranged in various different ways, forming structural isomers. The simplest isomer of an azane is the one in which the nitrogen atoms are arranged in a single chain with no branches. This isomer is sometimes called the n-isomer (n for "normal", although it is not necessarily the most common). However the chain of nitrogen atoms may also be branched at one or more points. The number of possible isomers increases rapidly with the number of nitrogen atoms. Due to the low energy of inversion, unsubstituted branched azanes cannot be

chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from i ...

. In addition to these isomers, the chain of nitrogen atoms may form one or more loops. Such compounds are called cycloazanes.

Nomenclature

The IUPAC nomenclature systematically naming nitrogen compounds by identifying hydronitrogen chains, analogous to the alkane nomenclature. Unbranched, saturated hydronitrogen chains are named with a Greek numerical prefix for the number of nitrogens and the suffix "-azane" for hydronitrogens with single bonds, or "-azene" for those with double bonds.Note that "-yne", which would be used for those with triple bonds, is absent because the only member of that series, N₂, is not a hydronitrogen.

Linear azanes

Straight-chain azanes are sometimes indicated by the prefix ''n''- (for ''normal'') where a non-linear isomer exists. Although this is not strictly necessary, the usage is common in cases where there is an important difference in properties between the straight-chain and branched-chain isomers. The members of the series (in terms of number of nitrogen atoms) are named as follows: :

, NH₃ - one nitrogen and three hydrogen :

diazane Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...

(or hydrazine), - two nitrogen and four hydrogen :

triazane Triazane is an inorganic compound with the chemical formula or . Triazane is the third simplest acyclic azane after ammonia and hydrazine. It can be synthesized from hydrazine but is unstable and cannot be isolated in the free base form, only a ...

, - three nitrogen and five hydrogen Azanes with three or more nitrogen atoms are named by adding the suffix -azane to the appropriate numerical multiplier prefix. Hence,

, ; tetrazane or tetraazane, ; pentazane or pentaazane, ; hexazane or hexaazane, ; etc. The prefix is generally Greek, with the exceptions of nonaazane which has a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

prefix, and undecaazane and tridecaazane which have mixed-language prefixes.

Hazards

Ammonia is explosive when mixed with air (15 – 25%). Other lower azanes can also form explosive mixtures with air. The lighter liquid azanes are highly flammable; this risk increases with the length of the nitrogen chain. One consideration for detection and risk control is that ammonia is lighter than air, creating the possibility of accumulation on ceilings.

Related and derived hydronitrogens

Related to the azanes are a homologous series of

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

s, side-chains, or radicals with the general chemical formula . Examples include

azanyl In chemistry, the amino radical, , also known as the aminyl radical or azanyl radical, is the neutral form of the amide ion (). Aminyl radicals are highly reactive and consequently short-lived, like most radicals; however, they form an import ...

() and hydrazinyl. This group is generally abbreviated with the symbol N.

References

{{Hydrides by group Inorganic compounds Nitrogen hydrides