Protactinium

Chemical, physical and material properties and data of the chemical element Protactinium.

Contents

General Information about Protactinium

Regular nameProtactiniumChemical symbolPaOther namesHistorical namesName meaning, originDiscovery (year)OccurencePosition in the PSEGroup membership

Atomar Properties of Protactinium

Atomic number Z91 = number of protonsStandard Atomic Weight231.03588 (1)

Electron configuration of Protactinium

1s	2s	2p	3s	3p	3d	4s	4p	4d	4f	5s	5p	5d	5f	6s	6p	6d	6f	7s	7p
2	2	6	2	6	10	2	6	10	14	2	6	10	2	2	6	1		2

Shorthand electron configuration of Protactinium: [Rn] 5f² 6d¹ 7s² .

Ionization Energies of Protactinium

The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volt (eV) per atom to separate a given electron from an Protactinium atom.

IE1
5.89

Isotopic Data of Protactinium

An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Protactinium isotopes.

Chemistry of Protactinium

Oxidation states+ 5Electronegativity1.5 (Pauling original)
1.50 (Pauling)Electron affinity0.55 eV
53.03 kJ mol^-1

Standard Electrode Potential

E⁰ (V)	Symbol	N_ox	Name Ox. Name Red.	Ox. Red.	e^-
-1.9	Pa	+ IV + III	Protactinium(IV) cation Protactinium(III) cation	Pa⁴⁺ ⇄ Pa³⁺	+ e^-
-1.49	Pa	+ IV 0	Protactinium(IV) cation Protactinium	Pa⁴⁺ ⇄ Pa (s)	+ 4 e^-
-1.34	Pa	+ III 0	Protactinium(III) cation Protactinium	Pa³⁺ ⇄ Pa (s)	+ 3 e^-

Material and Physical Properties

Melting point1572 °CEnthalpy of fusion (molar)12.34 kJ mol^-1Boiling point4027 °CEnthalpy of vaporization481 kJ mol^-1Density15.37 g cm^-3

External Data, Identifiers

CAS registry number7440-13-3InChI =1S/PaInChIKeyXLROVYAPLOFLNU-UHFFFAOYSA-NPubChem ID23945

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isotopes

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Last update: 2022-12-12

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