Periodic Table


Atomic number: 7
Atomic weight: 14.00674
Symbol: N
Group number: 15
Electronic configuration: [He].2s2.2p3


Nitrogen is a Group 15 element. Nitrogen makes up about 78% of the atmosphere by volume. The atmosphere of Mars contains less than 3% nitrogen. Nitrogen can be obtained by liquefaction and fractional distillation from air. The element seemed so inert that Lavoisier named it azote, meaning "without life". However, its compounds are vital components of foods, fertilizers, and explosives. Nitrogen gas is colourless, odourless, and generally inert. As a liquid it is also colourless and odourless, and is similar in appearance to water.

When nitrogen is heated, it combines directly with magnesium, lithium, or calcium. When mixed with oxygen and subjected to electric sparks, it forms nitric oxide (NO) and then the dioxide (NO2). When heated under pressure with hydrogen in the presence of a suitable catalyst , ammonia forms (Haber process). Nitrogen is "fixed" from the atmosphere by bacteria in the roots of certain plants such as clover. Hence the usefulness of clover in crop rotation.

General information

Discoveror: Daniel Rutherford
Date discovered: 1772
Discovered at: Scotland
Meaning of name: From the Greek words "nitron genes" meaning "nitre" and "forming" and the Latin word "nitrum" (nitre is a common name for potassium nitrate, KNO#)

Physical data

Standard state: gas at 298 K
Colour: colourless
Density of solid at ambient temperature/kg m-3: no data
Molar volume/cm3: 13.54

Radii /pm

Atomic: 56
Covalent (single bond):
Pauling radius for the ion [N]-: 247

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius53.952.3no datano data


Both values are quoted on the Pauling scale.

Pauling: 3.04
Allred Rochow: 3.07

Crystal Structure

structure: hcp (hexagonal close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 63.05
boiling point: 77.36

Enthalpies /kJ mol-1

fusion: 0.72
vaporization: 5.58

single bond enthalpies:
N-F N-Cl N-Br N-I N-N
283 313 no data no data 945.33

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
14N14.003074002 (26)99.634 (9)
15N15.00010897 (4)0.366 (9)

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/N.html