Protactini (Pa)

element with symbol Pa and atomic number of 91

Atomic Number	91
Atomic Weight	231.03588
Rhif màs	231

Group
Period	7
Block	f

Proton	91 p⁺
Niwtron	140 n⁰
Electron	91 e^-

Nodwedd Ffisegol

Atomic Radius	180 pm 285 pm
molar volume	15 cm³/mol
covalent radius	169 pm 138 pm 129 pm 200 pm
Metallic Radius
ionic radius	104 pm 90 pm 101 pm 78 pm 91 pm 95 pm 119.9 pm
Crystal Radius	118 pm 104 pm 115 pm 92 pm 105 pm 109 pm 133.9 pm
Van der Waals radius	243 pm 264 pm 342.4 pm
density	15.4 g/cm³

Nodwedd Gemegol

egni

proton affinity
electron affinity
ionization energy	5.89 eV/particle 11.9 eV/particle 19 eV/particle 30.9 eV/particle 44.3 eV/particle 72 eV/particle 85.1 eV/particle 98.9 eV/particle 111 eV/particle 137 eV/particle 153 eV/particle 187 eV/particle 203 eV/particle 292 eV/particle 316 eV/particle 342 eV/particle 369 eV/particle 395 eV/particle 423 eV/particle 460 eV/particle 488 eV/particle 518 eV/particle 546 eV/particle 690 eV/particle 720 eV/particle 760 eV/particle 790 eV/particle 880 eV/particle 920 eV/particle 1,020 eV/particle 1,060 eV/particle 1,150 eV/particle 1,220 eV/particle 1,300 eV/particle 1,370 eV/particle 1,450 eV/particle 1,520 eV/particle 1,600 eV/particle 1,670 eV/particle 1,760 eV/particle 1,830 eV/particle 1,910 eV/particle 2,000 eV/particle 2,060 eV/particle 2,130 eV/particle 2,483 eV/particle 2,550 eV/particle 2,620 eV/particle 2,696 eV/particle 2,766 eV/particle 2,837 eV/particle 2,968 eV/particle 3,040 eV/particle 3,119 eV/particle 3,193 eV/particle 3,488 eV/particle 3,558 eV/particle 3,637 eV/particle 3,709 eV/particle 4,077 eV/particle 4,161 eV/particle 4,370 eV/particle 4,454 eV/particle 7,181 eV/particle 7,341 eV/particle 7,510 eV/particle 7,690 eV/particle 7,870 eV/particle 8,040 eV/particle 8,410 eV/particle 8,590 eV/particle 8,780 eV/particle 8,960 eV/particle 9,460 eV/particle 9,620 eV/particle 9,790 eV/particle 9,950 eV/particle 11,100 eV/particle 11,280 eV/particle 11,660 eV/particle 11,840 eV/particle 24,660 eV/particle 25,080 eV/particle 25,540 eV/particle 25,970 eV/particle 30,230 eV/particle 30,800 eV/particle 31,520 eV/particle 31,971.6 eV/particle 126,296.6 eV/particle 128,507 eV/particle

enthalpy of vaporization	481.2 kJ/mol
enthalpy of fusion	16.7 kJ/mol
standard enthalpy of formation	563 kJ/mol
Electron

plisgyn yr electron	2, 8, 18, 32, 20, 9, 2

valence electron	2 ⓘ

trefn yr electronnau	[Rn] 5f² 6d¹ 7s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 5f² 6d¹ 7s²

Cyflwr ocsidiad	2, 3, 4, 5
Electronegatifedd	0.12149 1.5
Electrophilicity Index
cyflwr sylfaenol mater

cyflwr mater	Solid
gaseous state of matter
Boiling Point
Melting Point	1,845.15 K
critical pressure
critical temperature
triple point
appearance
lliw	Silver #ffffff #00a1ff #00a1ff
appearance	bright, silvery metallic luster
Mynegrif plygiant
nodwedd ffisegol gwrthrych
Thermal Conductivity
thermal expansion
molar heat capacity
Specific Heat Capacity
heat capacity ratio
electrical properties
type	Conductor
dargludedd trydanol	5.6 MS/m
Gwrthedd	0.00000018 Ω*m
superconductivity	1.41 K
magnetism
type	paramagnetic
magnetic susceptibility (Mass)	0.0000000325 m³/Kg
magnetic susceptibility (Molar)	0.000000007509 m³/mol
magnetic susceptibility (Volume)	0.0004995
magnetic ordering
Curie temperature
Néel temperature
strwythur
Crystal Structure	Centered Tetragonal (TET)
lattice constant	3.92 Å
Lattice Angles	π/2, π/2, π/2
nodwedd mecanyddol deunyddiau
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
speed of sound
classification
Category	Actinides, Actinides
CAS Group
IUPAC Group
Glawe Number	35
Mendeleev Number	18
Pettifor Number	46
Geochemical Class	U/Th decay series
Goldschmidt classification	litophile

other

Gas Basicity
polarizability	154 ± 20 a₀
C6 Dispersion Coefficient
allotrope
Neutron cross section	200
Neutron Mass Absorption
quantum number	4K11/2
space group	139 (I4/mmm)

Isotopes of Protactinium

Stable Isotopes	0
Unstable Isotopes	31
Natural Isotopes	1

²¹¹Pa

Rhif màs	211
neutron number	120
Relative Atomic Mass	211.023674036 ± 0.000074581 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	6 ± 3 ms
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	2006
parity	-

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
p (proton emission)

²¹²Pa

Rhif màs	212
neutron number	121
Relative Atomic Mass	212.023184819 ± 0.000094047 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	5.8 ± 1.9 ms
spin	3
nuclear quadrupole moment
dyddiad darganfod	1997
parity	+

decay mode	intensity
α (α emission)	100%

²¹³Pa

Rhif màs	213
neutron number	122
Relative Atomic Mass	213.021099644 ± 0.000061374 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	7.4 ± 2.4 ms
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	1995
parity	-

decay mode	intensity
α (α emission)	100%

²¹⁴Pa

Rhif màs	214
neutron number	123
Relative Atomic Mass	214.020891055 ± 0.00008718 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	17 ± 3 ms
spin	7
nuclear quadrupole moment
dyddiad darganfod	1995
parity	+

decay mode	intensity
α (α emission)	100%

²¹⁵Pa

Rhif màs	215
neutron number	124
Relative Atomic Mass	215.019113955 ± 0.000088513 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	14 ± 2 ms
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	1979
parity	-

decay mode	intensity
α (α emission)	100%

²¹⁶Pa

Rhif màs	216
neutron number	125
Relative Atomic Mass	216.019134633 ± 0.000026459 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	105 ± 12 ms
spin	5
nuclear quadrupole moment
dyddiad darganfod	1972
parity	+

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²¹⁷Pa

Rhif màs	217
neutron number	126
Relative Atomic Mass	217.018309024 ± 0.000013417 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	3.8 ± 0.2 ms
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	1968
parity	-

decay mode	intensity
α (α emission)	100%
β⁻ (β⁻ decay)

²¹⁸Pa

Rhif màs	218
neutron number	127
Relative Atomic Mass	218.020021133 ± 0.000019158 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	108 ± 5 us
spin	8
nuclear quadrupole moment
dyddiad darganfod	1979
parity	-

decay mode	intensity
α (α emission)	100%

²¹⁹Pa

Rhif màs	219
neutron number	128
Relative Atomic Mass	219.019949909 ± 0.000074831 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	56 ± 9 ns
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	2005
parity	-

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²²⁰Pa

Rhif màs	220
neutron number	129
Relative Atomic Mass	220.021769753 ± 0.000015732 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	0.85 ± 0.06 us
spin	1
nuclear quadrupole moment
dyddiad darganfod	2005
parity	-

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²²¹Pa

Rhif màs	221
neutron number	130
Relative Atomic Mass	221.021873393 ± 0.000063746 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	5.9 ± 1.7 us
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	1983
parity	-

decay mode	intensity
α (α emission)	100%

²²²Pa

Rhif màs	222
neutron number	131
Relative Atomic Mass	222.023687064 ± 0.000092975 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	3.8 ± 0.2 ms
spin	1
nuclear quadrupole moment
dyddiad darganfod	1970
parity	-

decay mode	intensity
α (α emission)	100%

²²³Pa

Rhif màs	223
neutron number	132
Relative Atomic Mass	223.023980414 ± 0.000081193 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	5.3 ± 0.3 ms
spin	9/2
nuclear quadrupole moment
dyddiad darganfod	1970
parity	-

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²²⁴Pa

Rhif màs	224
neutron number	133
Relative Atomic Mass	224.025617286 ± 0.000008145 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	844 ± 19 ms
spin	5
nuclear quadrupole moment
dyddiad darganfod	1958
parity	-

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²²⁵Pa

Rhif màs	225
neutron number	134
Relative Atomic Mass	225.026147927 ± 0.000087887 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	1.71 ± 0.1 s
spin	5/2
nuclear quadrupole moment
dyddiad darganfod	1958
parity	-

decay mode	intensity
α (α emission)	100%

²²⁶Pa

Rhif màs	226
neutron number	135
Relative Atomic Mass	226.027948217 ± 0.000012037 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	1.8 ± 0.2 m
spin	1
nuclear quadrupole moment
dyddiad darganfod	1949
parity	-

decay mode	intensity
α (α emission)	74%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	26%

²²⁷Pa

Rhif màs	227
neutron number	136
Relative Atomic Mass	227.028803586 ± 0.000007797 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	38.3 ± 0.3 m
spin	5/2
nuclear quadrupole moment
dyddiad darganfod	1948
parity	-

decay mode	intensity
α (α emission)	85%
ϵ (electron capture)	15%

²²⁸Pa

Rhif màs	228
neutron number	137
Relative Atomic Mass	228.031050758 ± 0.000004659 Da
g-factor	1.1666666666667 ± 0.16666666666667
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	22 ± 1 h
spin	3
nuclear quadrupole moment
dyddiad darganfod	1948
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	98.15%
α (α emission)	1.85%

²²⁹Pa

Rhif màs	229
neutron number	138
Relative Atomic Mass	229.032095585 ± 0.000003521 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	1.55 ± 0.04 d
spin	5/2
nuclear quadrupole moment
dyddiad darganfod	1949
parity	+

decay mode	intensity
ϵ (electron capture)	99.51%
α (α emission)	0.49%

²³⁰Pa

Rhif màs	230
neutron number	139
Relative Atomic Mass	230.034539717 ± 0.000003261 Da
g-factor	1 ± 0.1
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	17.4 ± 0.5 d
spin	2
nuclear quadrupole moment
dyddiad darganfod	1948
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	92.2%
β⁻ (β⁻ decay)	7.8%
α (α emission)	0.0032%

²³¹Pa

Rhif màs	231
neutron number	140
Relative Atomic Mass	231.0358825 ± 0.000001901 Da
g-factor	1.3266666666667 ± 0.013333333333333
natural abundance	100
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	32.65 ± 0.2 ky
spin	3/2
nuclear quadrupole moment	-1.72 ± 0.05
dyddiad darganfod	1918
parity	-

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	3%
24Ne (heavy cluster emission)	13.4%
23F	9.9%

²³²Pa

Rhif màs	232
neutron number	141
Relative Atomic Mass	232.038590205 ± 0.000008206 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	1.32 ± 0.02 d
spin	2
nuclear quadrupole moment
dyddiad darganfod	1949
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%
ϵ (electron capture)

²³³Pa

Rhif màs	233
neutron number	142
Relative Atomic Mass	233.040246535 ± 0.000001433 Da
g-factor	2.6666666666667 ± 0.46666666666667
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	26.975 ± 0.013 d
spin	3/2
nuclear quadrupole moment	-3 ± 0.4
dyddiad darganfod	1938
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

²³⁴Pa

Rhif màs	234
neutron number	143
Relative Atomic Mass	234.043305555 ± 0.000004395 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	6.7 ± 0.05 h
spin	4
nuclear quadrupole moment
dyddiad darganfod	1913
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

²³⁵Pa

Rhif màs	235
neutron number	144
Relative Atomic Mass	235.045399 ± 0.000015 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	24.4 ± 0.2 m
spin	3/2
nuclear quadrupole moment
dyddiad darganfod	1950
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

²³⁶Pa

Rhif màs	236
neutron number	145
Relative Atomic Mass	236.048668 ± 0.000015 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	9.1 ± 0.1 m
spin	1
nuclear quadrupole moment
dyddiad darganfod	1963
parity

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ SF (β⁻-delayed fission)	6%

²³⁷Pa

Rhif màs	237
neutron number	146
Relative Atomic Mass	237.051023 ± 0.000014 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	8.7 ± 0.2 m
spin	1/2
nuclear quadrupole moment	0
dyddiad darganfod	1954
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

²³⁸Pa

Rhif màs	238
neutron number	147
Relative Atomic Mass	238.054637 ± 0.000017 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	2.28 ± 0.09 m
spin	3
nuclear quadrupole moment
dyddiad darganfod	1968
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ SF (β⁻-delayed fission)	2.6%

²³⁹Pa

Rhif màs	239
neutron number	148
Relative Atomic Mass	239.05726 ± 0.00021 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes	1.8 ± 0.5 h
spin	1/2
nuclear quadrupole moment	0
dyddiad darganfod	1995
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

²⁴⁰Pa

Rhif màs	240
neutron number	149
Relative Atomic Mass	240.061203 ± 0.000215 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes
spin	3
nuclear quadrupole moment
dyddiad darganfod
parity	+

decay mode	intensity
β⁻ (β⁻ decay)

²⁴¹Pa

Rhif màs	241
neutron number	150
Relative Atomic Mass	241.064134 ± 0.000322 Da
g-factor
natural abundance
Dadfeilio ymbelydrol	☢️ elfen ymbelydrol
Hanner oes
spin	1/2
nuclear quadrupole moment	0
dyddiad darganfod
parity	+

decay mode	intensity
β⁻ (β⁻ decay)

hanes

darganfyddwr neu ddyfeisiwr	Fredrich Soddy, John Cranston, Otto Hahn, Lise Meitner
man darganfod	England/France
dyddiad darganfod	1917
geirdarddiad	Greek: proto and actinium (parent of actinium); it forms actinium when it radioactively decays.
ynganiad	PRO-tak-tin-eh-em (Saesneg)

source

Abundance
Abundance in Earth's crust	0.0000014 mg/kg
natural abundance (cefnfor)	0.00000000005 mg/L
natural abundance (corff dynol)	0 %
natural abundance (Awyrfaen)
natural abundance (Haul)
Abundance in Universe	0 %

Nuclear Screening Constants

Protactini on ChemicalAid

Australian Educational Vocabulary ID	scot/3563
CAB ID	7539
ChEBI ID	33386
ChemSpider ID	22387
DSSTOX compound identifier	DTXCID50147878
DSSTox substance ID	DTXSID50225387
Den Store Danske ID	protactinium
ECHA Substance Infocard ID	100.122.906
Elhuyar ZTH ID	030190
Encyclopedia of China ID (Second Edition)	224618
French Vikidia ID	Protactinium
GND	4175981-3
Great Russian Encyclopedia Online ID	3168919
ID NALT	3207
InChI	InChI=1S/Pa
InChIKey	XLROVYAPLOFLNU-UHFFFAOYSA-N
Namuwiki ID	프로트악티늄
National Library of Israel J9U ID	987007541390005171
OmegaWiki Defined Meaning	345414
OpenAlex ID	C505015426
PubChem CID	23945
Rhif Cofrestru CAS	7440-13-3
Römpp online ID	RD-16-04500
Store norske leksikon ID	protactinium
UNII	0S6855V29M
USGS Thesaurus ID	1547
WordNet 3.1 Synset ID	14675887-n
dynodwr Encyclopædia Britannica Online	science/protactinium
dynodwr Encyclopædia Universalis	protactinium
dynodwr Freebase	/m/025s7xw
dynodwr Gran Enciclopèdia Catalana	0135204
dynodwr KBpedia	Protactinium
dynodwr LCAuth	sh85107634
dynodwr MeSH	D011478
dynodwr Quora	Protactinium
dynodwr Treccani	protoattinio

Protactini (Pa)

Nodwedd Ffisegol

Nodwedd Gemegol

other

Isotopes of Protactinium

211Pa

212Pa

213Pa

214Pa

215Pa

216Pa

217Pa

218Pa

219Pa

220Pa

221Pa

222Pa

223Pa

224Pa

225Pa

226Pa

227Pa

228Pa

229Pa

230Pa

231Pa

232Pa

233Pa

234Pa

235Pa

236Pa

237Pa

238Pa

239Pa

240Pa

241Pa

hanes

source

Nuclear Screening Constants

²¹¹Pa

²¹²Pa

²¹³Pa

²¹⁴Pa

²¹⁵Pa

²¹⁶Pa

²¹⁷Pa

²¹⁸Pa

²¹⁹Pa

²²⁰Pa

²²¹Pa

²²²Pa

²²³Pa

²²⁴Pa

²²⁵Pa

²²⁶Pa

²²⁷Pa

²²⁸Pa

²²⁹Pa

²³⁰Pa

²³¹Pa

²³²Pa

²³³Pa

²³⁴Pa

²³⁵Pa

²³⁶Pa

²³⁷Pa

²³⁸Pa

²³⁹Pa

²⁴⁰Pa

²⁴¹Pa