Template:Infobox protactinium

Protactinium, ₉₁Pa

Small (a few cm) piece of silvery-gray metal in a sealed vial Sample of a protactinium-231 in a glass vial
Protactinium
Pronunciation	/ˌproʊtækˈtɪniəm/ ​(PROH-tak-TIN-ee-əm)
Appearance	bright, silvery metallic luster
Standard atomic weight Ar°(Pa)
	231.03588±0.00001 231.04±0.01 (abridged)
Protactinium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Pr ↑ Pa ↓ — thorium ← protactinium → uranium
Atomic number (Z)	91
Group	f-block groups (no number)
Period	period 7
Block	f-block
Electron configuration	[Rn] 5f2 6d1 7s2
Electrons per shell	2, 8, 18, 32, 20, 9, 2
Physical properties
Phase at STP	solid
Melting point	1841 K ​(1568 °C, ​2854 °F)
Boiling point	4300 K ​(4027 °C, ​7280 °F) (?)
Density (at 20° C)	15.43 g/cm3
Heat of fusion	12.34 kJ/mol
Heat of vaporization	481 kJ/mol
Atomic properties
Oxidation states	common: +5 +2,? +3, +4
Electronegativity	Pauling scale: 1.5
Ionization energies	1st: 568 kJ/mol
Atomic radius	empirical: 163 pm
Covalent radius	200 pm
Color lines in a spectral range Spectral lines of protactinium
Other properties
Natural occurrence	from decay
Crystal structure	​body-centered tetragonal (tI2)
Lattice constant	Body-centered tetragonal crystal structure for protactinium a = 392.1 pm c = 323.5 pm (at 20 °C)
Thermal expansion	11.8×10−6/K (at 20 °C)
Thermal conductivity	47 W/(m⋅K)
Electrical resistivity	177 nΩ⋅m (at 0 °C)
Magnetic ordering	paramagnetic
CAS Number	7440-13-3
History
Prediction	Dmitri Mendeleev (1869)
Discovery	Kasimir Fajans and Oswald Helmuth Göhring (1913)
First isolation	Aristid von Grosse (1934)
Named by	Otto Hahn and Lise Meitner (1917–8)
Isotopes of protactinium
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 229Pa synth 1.5 d ε 229Th 230Pa synth 17.4 d β+ 230Th β− 230U α 226Ac 231Pa 100% 3.265×104 y α 227Ac 232Pa synth 1.32 d β− 232U 233Pa trace 26.975 d β− 233U 234Pa trace 6.70 h β− 234U 234mPa trace 1.159 min β− 234U

Pa · Protactinium
Th ← ibox Th	iso 91 Pa  [] IB-Pa [] IBisos []	→ U ibox U
File:Symbol category class.svg cat:Pa (0) File:Symbol category class.svg cat:Pa-isotopes (0) File:Commons-logo.svg Commons File:Wikidata-logo.svg Wikidata:Q1109 File:Wiktionary-logo.svg Wiktionary
indexes by PT (page)

child table, as reused in {IB-Pa}
Main isotopes of protactinium
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 229Pa synth 1.5 d ε 229Th 230Pa synth 17.4 d β+ 230Th β− 230U α 226Ac 231Pa 100% 3.265×104 y α 227Ac 232Pa synth 1.32 d β− 232U 233Pa trace 26.975 d β− 233U 234Pa trace 6.70 h β− 234U 234mPa trace 1.159 min β− 234U

Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)	caption: alt:
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
most stable isotope
File:Notification-icon-Wikidata-logo.svg Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01) See also {{Index of data sets}} · Cat:data sets (0) · (this table: )

References

These references will appear in the article, but this list appears only on this page.