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calcium
Image: Wikimedia Commons

calcium

Chemical element with symbol Ca and atomic number 20

Chemical elementchemical elementlithophile elementactive metalQ706

Also known as element 20 · Ca · 20Ca

Symbol
Atomic number
  • 20
Mass
Melting point
  • 838.85°C
Boiling point
  • 1,483.85°C
Density
  • 1,534.82 kg/m³
Discovered by
Discovered
  • 1808

Overview

All data

175 statements · 31% with external sources · numbers in brackets are citations

Oxidation state
  • 2
  • 1
Canonical SMILES
Formula
Different from
Standard molar entropy
Electrical conductivity
Unicode character
Electronegativity
  • 1
Part of
Electron configuration
  • [Ar] 4s²
  • 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
Named after
  • lime language: Latin · subject named as: calx
Ionic radius
  • 1 ångström charge number: 2 · coordination number: 6
  • 1.12 charge number: 2 · coordination number: 8
  • 1.23 ångström charge number: 2 · coordination number: 10
  • 134 ångström charge number: 2 · coordination number: 12
Found in taxon
Show 6 more
Subject has role
Subclass of
Has use
Bulk modulus
  • 17.2B Pa
Shear modulus
  • 7.5B Pa
Poisson's ratio
  • 0.31
Thermal conductivity
  • 200 watt per metre kelvin
Specific heat capacity
  • 647.3 joule per kilogram kelvin
Speed of sound
  • 3,810 m/s
Electrical resistivity
  • 3.36e-8 ohm metre
Standard enthalpy of formation
  • 177.8 kilojoule per mole state of matter: gas
  • 7.79 kilojoule per mole state of matter: liquid
Mohs' hardness
  • 1.75
Has characteristic
Linear thermal expansion coefficient
  • 22.27 micrometre per metre kelvin temperature: 20°C
Ionization energy
Crystal system
Atomic radius
  • 180 picometre
Covalent radius
  • 176 picometre

On other databases

96 identifiers linking calcium across the web's reference databases