Skip to content
aidb
chromium
Image: Wikimedia Commons

chromium

Chemical element with symbol Cr and atomic number 24

Chemical elementchemical elementlithophile elementQ725

Also known as element 24 · 24Cr · Cr

Symbol
Atomic number
  • 24
Mass
Melting point
Boiling point
Density
  • 7.14 g/cm³
Discovered by
Discovered
  • 1797

Overview

All data

304 statements · 23% with external sources · numbers in brackets are citations

Named after
Oxidation state
  • 2
  • 3
  • 6
  • -2
  • -1
  • 1
  • 4
  • 5
Show 2 more
  • -4
  • 0
Subclass of
NIOSH Pocket Guide ID
  • 0141
Has effect
Immediately dangerous to life or health
  • 250 milligram per cubic metre
Vapor pressure
  • 0 millimetre of mercury temperature: 68°F
Time-weighted average exposure limit
  • 0.5 milligram per cubic metre applies to jurisdiction: none · runtime: 10 h
Subject has role
Unicode character
Electronegativity
  • 1.66
Part of
Different from
Found in taxon
Show 21 more
Formula
  • Cr
Canonical SMILES
  • [Cr]
Ionic radius
  • 0.73 ångström charge number: 2 · coordination number: 6
  • 0.62 ångström charge number: 3 · coordination number: 6
  • 0.41 ångström charge number: 4 · coordination number: 4
  • 0.55 ångström charge number: 4 · coordination number: 6
  • 0.26 ångström charge number: 6 · coordination number: 4
  • 0.44 ångström charge number: 6 · coordination number: 6
Electron configuration
  • [Ar] 3d⁵ 4s¹
Manufacturer
Associated hazard
Made from material
Bulk modulus
  • 234B Pa
Shear modulus
  • 77B Pa
Poisson's ratio
  • 0.352
Thermal conductivity
  • 94 watt per metre kelvin
Electrical conductivity
  • 7,870,000 siemens per metre
Specific heat capacity
  • 449 joule per kilogram kelvin
Speed of sound
  • 5,940 m/s
Electrical resistivity
  • 1.25e-7 ohm metre
Standard enthalpy of formation
  • 397.48 kilojoule per mole state of matter: gas
  • 26.07 kilojoule per mole state of matter: liquid
Standard molar entropy
  • 174.31 joule per mole kelvin state of matter: gas
  • 36.2 joule per mole kelvin state of matter: liquid
  • 23.62 joule per mole kelvin state of matter: solid
Mohs' hardness
  • 8.5
Linear thermal expansion coefficient
  • 4.81 micrometre per metre kelvin temperature: 20°C
Ionization energy
Has characteristic
Crystal system
Atomic radius
  • 140 picometre
Covalent radius
  • 139 picometre

On other databases

94 identifiers linking chromium across the web's reference databases