Nitrogen halides

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Structures of the nitrogen halides
Nitrogen trihalides
Pyramidal structure of the
nitrogen trihalides
Hydrogen Nitrogen Halides
Structure of the two possible
nitrogen-hydrogen halides:
the central N atom in blue,
the halogen atoms (X) in red
Dinitrogen tetrahalides
Structure of the dinitrogen tetrahalides:
the halogen atoms (X) are each red,
note the lone
electron pairs (in blue)
Dinitrogen Dihalides
Structure of the dinitrogen dihalides:
cis / trans isomers occur here

Nitrogen halides are binary compounds of nitrogen with halogens . Most of the known representatives have the composition NX 3 (with X = halogen), but halogen amines or halide hydrides and compounds with two or three nitrogen atoms per molecule are also known.

Nitrogen trihalides NX 3

The nitrogen trihalides, analogous to ammonia (NH 3 ), have a pyramidal structure with 3 equivalent halogen atoms. In addition to nitrogen trifluoride, these nitrogen halides are endothermic compounds that explode when heated or sometimes when touched. The following pyramidal nitrogen trihalides are known:

The stability, color and structure of the nitrogen trihalides also vary with the halogen involved:

  • the colorless fluoride and the yellow chloride form relatively stable single molecules that only decompose when heated,
  • the extremely unstable, red bromide can form both monomeric and polymeric modifications,
  • the highly explosive iodide is only available as a black polymer .

Hydrogen Nitrogen Halides

In addition to binary halides, pyramidal hydrogen nitrogen halides or nitrogen halide hydrides of the types NHX 2 and NH 2 X, which are also referred to as halogen amines , have also been found . These are not binary compounds and in the strict sense not nitrogen halides, but most textbooks still include them in this group. This includes:

Monohalamines NH 2 X

Dihalogenamine NHX 2

Higher nitrogen halides

In addition to the simple-pyramidal nitrogen trihalides and halogenamines derived from ammonia, there are also some compounds with two or three nitrogen atoms in the molecule. The dinitrogen tetrahalides N 2 X 4 have a bipyramidal structure, similar to ethane , but with one hydrogen atom replaced by a free electron pair or analogously to hydrazine . The dinitrogen dihalides N 2 X 2 have an N = N double bond and cis-trans isomers occur. The halogen azides N 3 X are derivatives of hydrazoic acid and have the same structure. The only stable, non-endothermic compound is dinitrogen tetrafluoride , all other compounds can only be represented at low temperatures and are sensitive to impact and temperature increases.

Dinitrogen tetrahalides N 2 X 4

Dinitrogen dihalides N 2 X 2

Halogen azides N 3 X

Overview of important properties

Properties of the nitrogen halides
Hydrogen Nitrogen Monohalides
Surname Monofluoroamine Monochloramine Monobromamine Monoiodamine
Brief description colorless gas colorless gas red-purple substance black substance
Discovery (year, person) 1988, Minkwitz 1923, Marckwand, Wille ? 1962, Jander
Smp./Sdp. ( ° C ) ~ −100 ° C (dec.) / - ~ −70 ° C,> −110 ° C dec. ? > −90 ° C dec.
ΔH f 0 (kJ) (= standard enthalpy of formation ) ? 390 kJ ? ?
Hydrogen Nitrogen Dihalides
Surname Difluoroamine Dichloramine Dibromoamine Diiodamine
Brief description colorless gas yellow gas orange substance black substance
Discovery (year, person) 1931, Ruff 1929, Chapin 1958, Jander 1962, Jander
Smp./Sdp. ( ° C ) −116.4 ° C / −23.6 ° C decomposition ? > −60 ° C dec.
ΔH f 0 (kJ) −67 kJ ? ? ?
Nitrogen trihalides
Surname Nitrogen trifluoride Nitrogen trichloride Nitrogen tribromide Nitrogen triiodide
Brief description colorless gas yellow oil deep red crystals deep red substance
Discovery (year, person) 1928, Ruff 1811, Dulong 1975, Jander 1990, Klapötke
Smp./Sdp. ( ° C ) −206.8 ° C / −129.0 ° C −40 ° C / 71 ° C > −100 ° C explosion > −78 ° C dec.
ΔH f 0 (kJ) −125 kJ + 229 kJ ? + 290 kJ
Dinitrogen tetrahalides
Surname Nitrous tetrafluoride Nitrous tetrachloride Dinitrogen tetrabromide Dinitrogen tetraiodide
Brief description colorless gas ? - -
Discovery (year, person) 1957, Colburn ? - -
Smp./Sdp. ( ° C ) −164.5 ° C / −73 ° C ? - -
ΔH f 0 (kJ) ? ? - -
Dinitrogen Dihalides
Surname Dinitrogen difluoride Nitrous dichloride Nitrous dibromide Nitrous diiodide
Brief description colorless gas ? - -
Discovery (year, person) 1942, Haller ? - -
Smp./Sdp. ( ° C ) trans: −172 ° C / −114.4 ° C

cis: −195 ° C / −105.7 ° C

? - -
ΔH f 0 (kJ) trans: 82.1 kJ

cis: 69.5 kJ

? - -
Tri-nitrogen monohalides / halogen azides
Surname Fluoroazide Chloride azide Bromine azide Iodine azide
Brief description green-yellow gas colorless gas orange-red liquid colorless substance
Discovery (year, person) 1942, Haller 1908, Raschig 1925, Spencer 1900, Hantzsch
Smp./Sdp. ( ° C ) −154 ° C / −82 ° C −100 ° C / −15 ° C −45 ° C / explosion ~ 20 ° C / explosion
ΔH f 0 (kJ) ? + 390 kJ + 385 kJ ?
"?" = Value not known , "-" = substance not known

Individual evidence

  1. ^ A b c A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , pp. 678-688.
  2. ↑ a b c Nikolaus Korber: nitrogen halides , inorganic chemistry, lecture script, University of Regensburg
  3. ↑ HP Latscha, HA Klein: Inorganic Chemistry . Springer, 2002, ISBN 3-540-42938-7 , p. 312ff.
  4. ^ J. Jander: Non-Aqueous Solvents for Preparation and Reactions of Nitrogen Halogen Compounds . (PDF; 465 kB) Pure Appl. Chem. , Vol. 49, Pergamon, 1977, pp. 67-73.
  5. ↑ a b c d e connection has not yet been detected.