ELEMENTLE

Element 49 · Metal

Indium

Period 5 · Group 13

Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metallic element that is rare in Earth's crust. The metal is very soft, malleable and easily fusible, with a melting point higher than sodium, but lower than lithium or tin.

Three reasons Indium stands out

  1. 1

    A soft and safe metal for chewing.

  2. 2

    Its tin oxide compound is the transparent conductor coating found on virtually every LCD touchscreen in the world.

  3. 3

    It makes a distinctive high-pitched crackling sound, known as a "cry," when a bar of it is bent.

The quiet ingredient in every touchscreen

Indium is soft enough to mark paper and squeaks when bent, but its most familiar role is invisible. Indium tin oxide combines transparency with electrical conductivity, creating the clear electrodes in touchscreens and displays. Most indium is recovered as a by-product of zinc processing.

Indium at a glance
Atomic number / protons49
SymbolIn
Family (Elementle)Metal
Classification (PubChem)Post-transition metal
Period5
Group13
Atomic mass (u)114.818
Standard stateSolid
Electron configuration[Kr]5s2 4d10 5p1
Reported oxidation states+3
Electronegativity (Pauling)1.78
Atomic radius (pm)193
First ionization energy (eV)5.786
Electron affinity (eV)0.3
Density (g/cm³)7.31
Melting point429.75 K (156.6 °C)
Boiling point2345 K (2,071.85 °C)
Discovery (PubChem)1863

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Indium · Indium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.