Periodic Table


Atomic number: 49
Atomic weight: 114.818
Symbol: In
Group number: 13
Electronic configuration: [Kr].4d10.5s2.5p1


Indium is a very soft, silvery-white metal with a brilliant lustre. The pure metal gives a high-pitched "scream" when bent. It wets glass, as does gallium. It is useful for making low-melting alloys. An alloy of 24% indium and 76% gallium is liquid at room temperature. Canada produces the majority of of the world's supply of indium.

General information

Discoveror: Ferdinand Reich, Hieronymus Theodor Richter
Date discovered: 1863
Discovered at: Germany
Meaning of name: Named after the indigo line in its atomic spectrum

Physical data

Standard state: solid at 298 K
Colour: silvery lustrous grey
Density of solid at ambient temperature/kg m-3: 7310
Molar volume/cm3: 15.76

Radii /pm

Atomic: 156
Covalent (single bond):
Pauling radius for the ion [In]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius123.4158.449.1no data


Both values are quoted on the Pauling scale.

Pauling: 1.78
Allred Rochow: 1.49

Crystal Structure

structure: tetragonal

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: 429.75
boiling point: 2345

Enthalpies /kJ mol-1

fusion: 3.26
vaporization: 229

single bond enthalpies:
In-F In-Cl In-Br In-I In-In
444 328 279 225 100

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
113In112.904061 (4)4.3 (2)
115In114.903882 (4)95.7 (2)

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/In.html