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protactinium
Image: Wikimedia Commons

protactinium

Element with symbol Pa and atomic number of 91

Chemical elementchemical elementQ1109

Also known as protoactinium · brevium · Pa · 91Pa · element 91

Symbol
Atomic number
  • 91
Mass
Melting point
  • 1,843 K
Boiling point
  • 4,300 K
Density
  • 15,684.3 kg/m³
Discovered by
Discovered
  • 1917

Overview

All data

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

Named after
Electronegativity
  • 2
Canonical SMILES
Formula
Unicode character
Part of
Ionic radius
  • 1.04 ångström charge number: 3 · coordination number: 6
  • 0.9 ångström charge number: 4 · coordination number: 6
  • 0.78 ångström charge number: 5 · coordination number: 6
Space group
Crystal system
Bulk modulus
  • 96.2B Pa
Shear modulus
  • 11.4B Pa
Poisson's ratio
  • 0.443
Thermal conductivity
  • 47 watt per metre kelvin
Electrical conductivity
  • 5,560,000 siemens per metre
Subclass of
Point group
Linear thermal expansion coefficient
  • 11.8 micrometre per metre kelvin temperature: 20°C
Electron configuration
IPA transcription
  • ˌproʊtækˈtɪniəm language: English
Oxidation state
  • 5
  • 2
  • 3
  • 4
Has characteristic
Atomic radius
  • 180 picometre
Covalent radius
  • 200 picometre

On other databases

56 identifiers linking protactinium across the web's reference databases