Americium (Am)

chemical element with the atomic number of 95

Atomic Number	95
Atomic Weight	243
mass number	223

Group
Period	7
Block	f

proton	95 p⁺
neutron	128 n⁰
electron	95 e^-

Physical Property

Atomic Radius	175 pm 276 pm
molar volume	20,8 cm³/mol
Covalent Radius	166 pm 135 pm 180 pm
Metallic Radius
ionic radius	121 pm 126 pm 131 pm 97,5 pm 109 pm 85 pm 95 pm 115,7 pm
Crystal Radius	135 pm 140 pm 145 pm 111,5 pm 123 pm 99 pm 109 pm 129,7 pm
Van der Waals radius	244 pm 338,1 pm
density	12 g/cm³

Chemical Property

energy

proton affinity
electron affinity
ionization energy	5,9738 eV/particle 11,7 eV/particle 21,7 eV/particle 36,8 eV/particle 50 eV/particle 67,9 eV/particle 95 eV/particle 110 eV/particle 126 eV/particle 141 eV/particle 162 eV/particle 184 eV/particle 206 eV/particle 225 eV/particle 242 eV/particle 284 eV/particle 305 eV/particle 424 eV/particle 451 eV/particle 481 eV/particle 511 eV/particle 541 eV/particle 571 eV/particle 616 eV/particle 646 eV/particle 680 eV/particle 711 eV/particle 860 eV/particle 900 eV/particle 940 eV/particle 980 eV/particle 1 090 eV/particle 1 130 eV/particle 1 240 eV/particle 1 280 eV/particle 1 410 eV/particle 1 490 eV/particle 1 570 eV/particle 1 650 eV/particle 1 740 eV/particle 1 820 eV/particle 1 900 eV/particle 1 980 eV/particle 2 070 eV/particle 2 160 eV/particle 2 240 eV/particle 2 320 eV/particle 2 410 eV/particle 2 000 eV/particle 2 874 eV/particle 2 946 eV/particle 3 021 eV/particle 3 101 eV/particle 3 178 eV/particle 3 251 eV/particle 3 402 eV/particle 3 479 eV/particle 3 563 eV/particle 3 641 eV/particle 3 956 eV/particle 4 033 eV/particle 4 115 eV/particle 4 191 eV/particle 4 642 eV/particle 4 733 eV/particle 4 960 eV/particle 5 050 eV/particle 8 040 eV/particle 8 210 eV/particle 8 400 eV/particle 8 590 eV/particle 8 770 eV/particle 8 950 eV/particle 9 380 eV/particle 9 560 eV/particle 9 770 eV/particle 9 960 eV/particle 10 490 eV/particle 10 650 eV/particle 10 830 eV/particle 11 000 eV/particle 12 400 eV/particle 12 600 eV/particle 13 000 eV/particle 13 190 eV/particle 27 110 eV/particle 27 550 eV/particle 28 040 eV/particle 28 500 eV/particle 33 700 eV/particle 34 300 eV/particle 35 100 eV/particle 35 549,4 eV/particle 139 769,5 eV/particle 142 161 eV/particle

enthalpy of vaporization	238,5 kJ/mol
enthalpy of fusion	10 kJ/mol
standard enthalpy of formation	284 kJ/mol
electron

electron shell	2, 8, 18, 32, 25, 8, 2

valence electron	2 ⓘ

electron configuration	[Rn] 5f⁷ 7s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 5f⁷ 7s²

oxidation number	2, 3, 4, 5, 6, 7
electronegativity	0.17194
Electrophilicity Index
fundamental state of matter

phase of matter	Solid
gaseous state of matter
Boiling Point
Melting Point	1 449,15 K
critical pressure
critical temperature
triple point
appearance
color	Silver #ffffff #545cf2 #545cf2
appearance	silvery white
refractive index
thermodynamic material property
Thermal Conductivity
thermal expansion
molar heat capacity
Specific Heat Capacity
heat capacity ratio
electrical properties
type
electrical conductivity
electrical resistivity
superconductivity	0,6 K
magnetism
type	paramagnetic
magnetic susceptibility (Mass)	0,0000000515 m³/Kg
magnetic susceptibility (Molar)	0,00000001251 m³/mol
magnetic susceptibility (Volume)	0,000704
magnetic ordering
Curie temperature
Néel temperature
structure
Crystal Structure	Simple Hexagonal ()
lattice constant
Lattice Angles	π/2, π/2, 2 π/3
mechanical property
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
speed of sound
classification
Category	Actinides, Actinides
CAS Group
IUPAC Group
Glawe Number	39
Mendeleev Number	26
Pettifor Number	42
Geochemical Class
Goldschmidt classification	synthetic

other

Gas Basicity
polarizability	131 ± 25 a₀
C6 Dispersion Coefficient
allotrope
Neutron cross section	74
Neutron Mass Absorption
quantum number	8S7/2
space group	194 (P63/mmc)

Isotopes of Americium

Stable Isotopes	0
Unstable Isotopes	27
Natural Isotopes	0

²²³Am

mass number	223
neutron number	128
Relative Atomic Mass	223,04584 ± 0,000322 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	10 ± 9 ms
spin	9/2
nuclear quadrupole moment
time of discovery or invention	2015
parity	-

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

²²⁴Am

mass number	224
neutron number	129
Relative Atomic Mass	224,046442 ± 0,000429 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin
nuclear quadrupole moment
time of discovery or invention
parity

decay mode	intensity
α (α emission)
SF (spontaneous fission)

²²⁵Am

mass number	225
neutron number	130
Relative Atomic Mass	225,045508 ± 0,000429 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	9/2
nuclear quadrupole moment
time of discovery or invention
parity	-

decay mode	intensity
α (α emission)
SF (spontaneous fission)

²²⁶Am

mass number	226
neutron number	131
Relative Atomic Mass	226,04613 ± 0,000322 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin
nuclear quadrupole moment
time of discovery or invention
parity

decay mode	intensity
α (α emission)
SF (spontaneous fission)

²²⁷Am

mass number	227
neutron number	132
Relative Atomic Mass	227,045282 ± 0,000215 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	9/2
nuclear quadrupole moment
time of discovery or invention
parity	-

decay mode	intensity
α (α emission)
SF (spontaneous fission)

²²⁸Am

mass number	228
neutron number	133
Relative Atomic Mass	228,046001 ± 0,000215 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin
nuclear quadrupole moment
time of discovery or invention
parity

decay mode	intensity
α (α emission)
SF (spontaneous fission)

²²⁹Am

mass number	229
neutron number	134
Relative Atomic Mass	229,045282534 ± 0,000114169 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	1,8 ± 1,5 s
spin	5/2
nuclear quadrupole moment
time of discovery or invention	2015
parity	-

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

²³⁰Am

mass number	230
neutron number	135
Relative Atomic Mass	230,046025 ± 0,000153 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	40 ± 9 s
spin	1
nuclear quadrupole moment
time of discovery or invention	2003
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ SF (β⁺-delayed fission)	30%

²³¹Am

mass number	231
neutron number	136
Relative Atomic Mass	231,045529 ± 0,000322 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	5/2
nuclear quadrupole moment
time of discovery or invention
parity	-

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

²³²Am

mass number	232
neutron number	137
Relative Atomic Mass	232,046613 ± 0,000322 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	1,31 ± 0,04 m
spin	1
nuclear quadrupole moment
time of discovery or invention	1967
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	97%
α (α emission)
β⁺ SF (β⁺-delayed fission)	0.069%

²³³Am

mass number	233
neutron number	138
Relative Atomic Mass	233,046468 ± 0,000123 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	3,2 ± 0,8 m
spin	5/2
nuclear quadrupole moment
time of discovery or invention	2000
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)	4.5%

²³⁴Am

mass number	234
neutron number	139
Relative Atomic Mass	234,047731 ± 0,000172 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	2,32 ± 0,08 m
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1967
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	0.039%
β⁺ SF (β⁺-delayed fission)	0.0066%

²³⁵Am

mass number	235
neutron number	140
Relative Atomic Mass	235,047906478 ± 0,000056661 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	10,3 ± 0,6 m
spin	5/2
nuclear quadrupole moment
time of discovery or invention	1996
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	99.6%
α (α emission)	0.4%

²³⁶Am

mass number	236
neutron number	141
Relative Atomic Mass	236,049427 ± 0,000127 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	3,6 ± 0,1 m
spin	5
nuclear quadrupole moment
time of discovery or invention	1998
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	4%

²³⁷Am

mass number	237
neutron number	142
Relative Atomic Mass	237,049995 ± 0,000064 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	73,6 ± 0,8 m
spin	5/2
nuclear quadrupole moment
time of discovery or invention	1970
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	99.975%
α (α emission)	0.025%

²³⁸Am

mass number	238
neutron number	143
Relative Atomic Mass	238,051982531 ± 0,000063243 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	98 ± 3 m
spin	1
nuclear quadrupole moment
time of discovery or invention	1950
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	1%

²³⁹Am

mass number	239
neutron number	144
Relative Atomic Mass	239,053022729 ± 0,000002127 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	11,9 ± 0,1 h
spin	5/2
nuclear quadrupole moment
time of discovery or invention	1949
parity	-

decay mode	intensity
ϵ (electron capture)	99.99%
α (α emission)	0.01%

²⁴⁰Am

mass number	240
neutron number	145
Relative Atomic Mass	240,055298374 ± 0,000014849 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	50,8 ± 0,3 h
spin	3
nuclear quadrupole moment
time of discovery or invention	1949
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	1.9%

²⁴¹Am

mass number	241
neutron number	146
Relative Atomic Mass	241,056827343 ± 0,000001195 Da
g-factor	0,64 ± 0,004
natural abundance
radioactivity	☢️ radioactive element
half-life	432,6 ± 0,6 y
spin	5/2
nuclear quadrupole moment	4,34 ± 0,05
time of discovery or invention	1949
parity	-

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	3.6%

²⁴²Am

mass number	242
neutron number	147
Relative Atomic Mass	242,059547358 ± 0,000001199 Da
g-factor	0,3854 ± 0,0017
natural abundance
radioactivity	☢️ radioactive element
half-life	16,02 ± 0,02 h
spin	1
nuclear quadrupole moment	−2,4 ± 0,4
time of discovery or invention	1949
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	82.7%
ϵ (electron capture)	17.3%

²⁴³Am

mass number	243
neutron number	148
Relative Atomic Mass	243,061379889 ± 0,00000149 Da
g-factor	0,608 ± 0,004
natural abundance
radioactivity	☢️ radioactive element
half-life	7,35 ± 0,009 ky
spin	5/2
nuclear quadrupole moment	4,32 ± 0,06
time of discovery or invention	1950
parity	-

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	3.7%

²⁴⁴Am

mass number	244
neutron number	149
Relative Atomic Mass	244,064282892 ± 0,0000016 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	10,01 ± 0,03 h
spin	6
nuclear quadrupole moment
time of discovery or invention	1950
parity	-

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

²⁴⁵Am

mass number	245
neutron number	150
Relative Atomic Mass	245,066452827 ± 0,000002024 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	2,05 ± 0,01 h
spin	5/2
nuclear quadrupole moment
time of discovery or invention	1955
parity	+

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

²⁴⁶Am

mass number	246
neutron number	151
Relative Atomic Mass	246,069774 ± 0,000019 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	39 ± 3 m
spin	7
nuclear quadrupole moment
time of discovery or invention	1955
parity	-

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

²⁴⁷Am

mass number	247
neutron number	152
Relative Atomic Mass	247,072092 ± 0,000107 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	23 ± 1,3 m
spin	5/2
nuclear quadrupole moment
time of discovery or invention	1967
parity

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

²⁴⁸Am

mass number	248
neutron number	153
Relative Atomic Mass	248,075752 ± 0,000215 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	3
nuclear quadrupole moment
time of discovery or invention
parity	+

decay mode	intensity
β⁻ (β⁻ decay)

²⁴⁹Am

mass number	249
neutron number	154
Relative Atomic Mass	249,07848 ± 0,00032 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	5/2
nuclear quadrupole moment
time of discovery or invention
parity

decay mode	intensity
β⁻ (β⁻ decay)

history

discoverer or inventor	G.T.Seaborg, R.A.James, L.O.Morgan, A.Ghiorso
location of discovery	United States
time of discovery or invention	1945
etymology	Named for the American continent, by analogy with europium.
pronunciation	am-er-ISH-i-em (engelsk)

source

Abundance
Abundance in Earth's crust
natural abundance (ocean)
natural abundance (human body)	0 %
natural abundance (meteoroid)	0 %
natural abundance (Sun)	0 %
Abundance in Universe	0 %

Nuclear Screening Constants

Americium on ChemicalAid

Australian Educational Vocabulary ID	scot/1091
CAB ID	7535
CAS Registry Number	7440-35-9
ChEBI ID	33389
ChemSpider ID	22405
DSSTOX compound identifier	DTXCID6047658
DSSTox substance ID	DTXSID3064693
Den Store Danske ID	americium
ECHA Substance Infocard ID	100.028.313
Elhuyar ZTH ID	020208
Encyclopedia of China ID (Second Edition)	220632
Encyclopædia Britannica Online ID	science/americium
Encyclopædia Universalis ID	americium
Freebase ID	/m/027sxty
French Vikidia ID	Américium
GND ID	4191405-3
Great Russian Encyclopedia Online ID	1817972
InChI	InChI=1S/Am
InChIKey	LXQXZNRPTYVCNG-UHFFFAOYSA-N
KBpedia ID	Americium
Library of Congress authority ID	sh85004443
MeSH descriptor ID	D000576
NDL Authority ID	00575178
National Library of Israel J9U ID	987007294067605171
OmegaWiki Defined Meaning	155847
OpenAlex ID	C552554468
PDB ligand ID	AM
PDB structure ID	4ZHG
PubChem CID	23966
Römpp online ID	RD-01-01920
Store norske leksikon ID	americium
Treccani ID	americio
UNII	VW92PHU2UY
USGS Thesaurus ID	1392
WordNet 3.1 Synset ID	14652672-n

Americium (Am)

Physical Property

Chemical Property

other

Isotopes of Americium

223Am

224Am

225Am

226Am

227Am

228Am

229Am

230Am

231Am

232Am

233Am

234Am

235Am

236Am

237Am

238Am

239Am

240Am

241Am

242Am

243Am

244Am

245Am

246Am

247Am

248Am

249Am

history

source

Nuclear Screening Constants

²²³Am

²²⁴Am

²²⁵Am

²²⁶Am

²²⁷Am

²²⁸Am

²²⁹Am

²³⁰Am

²³¹Am

²³²Am

²³³Am

²³⁴Am

²³⁵Am

²³⁶Am

²³⁷Am

²³⁸Am

²³⁹Am

²⁴⁰Am

²⁴¹Am

²⁴²Am

²⁴³Am

²⁴⁴Am

²⁴⁵Am

²⁴⁶Am

²⁴⁷Am

²⁴⁸Am

²⁴⁹Am