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selenium
Image: Wikimedia Commons

selenium

Chemical element with symbol Se and atomic number 34

Chemical elementchemical elementflammable solidchalcophile elementQ876

Also known as Se · element 34 · 34Se

Symbol
Atomic number
Mass
Melting point
Boiling point
Density
Discovered by
Discovered
  • 1817

Overview

All data

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

Named after
Electronegativity
  • 2.55
Oxidation state
  • -2
  • 2
  • 4
  • 6
  • 1
  • -1
  • 0
  • 3
Show 1 more
  • 5
Subclass of
NIOSH Pocket Guide ID
  • 0550
Has effect
Immediately dangerous to life or health
Vapor pressure
Time-weighted average exposure limit
Canonical SMILES
Formula
Medical condition treated
Subject has role
Location of discovery
Unicode character
Part of
Ionic radius
  • 0.5 ångström charge number: 4 · coordination number: 6
  • 0.28 ångström charge number: 6 · coordination number: 4
  • 0.42 ångström charge number: 6 · coordination number: 6
Associated hazard
Made from material
Thermal conductivity
  • 0.52 watt per metre kelvin
Speed of sound
  • 3,350 m/s
Mohs' hardness
  • 2
Has characteristic
Ionization energy
Electron configuration
IPA transcription
Crystal system
Atomic radius
  • 115 picometre
Covalent radius
  • 120 picometre
Van der Waals radius
  • 190 picometre

On other databases

89 identifiers linking selenium across the web's reference databases