Femu (Fm)

chemical element with the atomic number of 100

Atomic Number	100
Atomic Weight	257
mass number	241

Group
Period	7
Block	f

Proton	100 p⁺
Netron	141 n⁰
Eléktron	100 e^-

Physical Property

Atomic Radius
molar volume
covalent radius	167 pm
Metallic Radius
ionic radius	110,5 pm
Crystal Radius	124,5 pm
Van der Waals radius	245 pm 328,6 pm
density	9,7 g/cm³

Chemical Property

molungé

proton affinity
electron affinity
ionization energy	6,5 eV/particle 10 eV/particle 23,2 eV/particle 39,3 eV/particle 55 eV/particle 74 eV/particle 93 eV/particle 120 eV/particle 136 eV/particle 162 eV/particle 185 eV/particle 209 eV/particle 237 eV/particle 257 eV/particle 276 eV/particle 300 eV/particle 326 eV/particle 351 eV/particle 377 eV/particle 402 eV/particle 430 eV/particle 453 eV/particle 616 eV/particle 647 eV/particle 680 eV/particle 716 eV/particle 749 eV/particle 782 eV/particle 837 eV/particle 871 eV/particle 909 eV/particle 944 eV/particle 1.110 eV/particle 1.150 eV/particle 1.190 eV/particle 1.230 eV/particle 1.370 eV/particle 1.420 eV/particle 1.550 eV/particle 1.600 eV/particle 1.770 eV/particle 1.860 eV/particle 1.940 eV/particle 2.030 eV/particle 2.120 eV/particle 2.210 eV/particle 2.300 eV/particle 2.390 eV/particle 2.490 eV/particle 2.590 eV/particle 2.680 eV/particle 2.760 eV/particle 2.900 eV/particle 2.950 eV/particle 3.403 eV/particle 3.480 eV/particle 3.561 eV/particle 3.647 eV/particle 3.730 eV/particle 3.810 eV/particle 3.986 eV/particle 4.070 eV/particle 4.160 eV/particle 4.245 eV/particle 4.586 eV/particle 4.670 eV/particle 4.760 eV/particle 4.840 eV/particle 5.420 eV/particle 5.510 eV/particle 5.760 eV/particle 5.860 eV/particle 9.200 eV/particle 9.370 eV/particle 9.570 eV/particle 9.770 eV/particle 9.970 eV/particle 10.160 eV/particle 10.660 eV/particle 10.860 eV/particle 11.080 eV/particle 11.280 eV/particle 11.850 eV/particle 12.020 eV/particle 12.220 eV/particle 12.390 eV/particle 14.180 eV/particle 14.400 eV/particle 14.800 eV/particle 15.000 eV/particle 30.300 eV/particle 30.800 eV/particle 31.300 eV/particle 31.800 eV/particle 38.400 eV/particle 39.100 eV/particle 40.000 eV/particle 40.482,2 eV/particle 158.152,5 eV/particle 160.804 eV/particle

enthalpy of vaporization
enthalpy of fusion
standard enthalpy of formation
Eléktron

electron shell	2, 8, 18, 32, 30, 8, 2

valence electron	2 ⓘ

electron configuration	[Rn] 5f¹² 7s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 5f¹² 7s²

oxidation number	2, 3
electronegativity	0.22485
Electrophilicity Index
fundamental state of matter

phase of matter	Solid
gaseous state of matter
Boiling Point
Melting Point	1.800,15 K
critical pressure
critical temperature
triple point
appearance
Lángi	Colorless #ffffff #b31fba #b31fba
appearance
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
magnetism
type
magnetic susceptibility (Mass)
magnetic susceptibility (Molar)
magnetic susceptibility (Volume)
magnetic ordering
Curie temperature
Néel temperature
structure
Crystal Structure	()
lattice constant
Lattice Angles
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	44
Mendeleev Number	36
Pettifor Number	37
Geochemical Class
Goldschmidt classification	synthetic

other

Gas Basicity
polarizability	113 ± 20 a₀
C6 Dispersion Coefficient
allotrope
Neutron cross section	5.800
Neutron Mass Absorption
quantum number	3H6
space group	()

Isotopes of Fermium

Stable Isotopes	0
Unstable Isotopes	20
Natural Isotopes	0

²⁴¹Fm

mass number	241
neutron number	141
Relative Atomic Mass	241,074311 ± 0,000322 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	730 ± 60 us
spin	5/2
nuclear quadrupole moment
time of discovery or invention	2008
parity	+

decay mode	intensity
SF (spontaneous fission)
α (α emission)	14%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	12%

²⁴²Fm

mass number	242
neutron number	142
Relative Atomic Mass	242,07343 ± 0,00043 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	800 ± 200 us
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1975
parity	+

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

²⁴³Fm

mass number	243
neutron number	143
Relative Atomic Mass	243,074414 ± 0,00014 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	231 ± 9 ms
spin	7/2
nuclear quadrupole moment
time of discovery or invention	1981
parity	-

decay mode	intensity
α (α emission)	91%
SF (spontaneous fission)	9%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²⁴⁴Fm

mass number	244
neutron number	144
Relative Atomic Mass	244,074036 ± 0,000216 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	3,12 ± 0,08 ms
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1967
parity	+

decay mode	intensity
SF (spontaneous fission)	97%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	2%
α (α emission)	1%

²⁴⁵Fm

mass number	245
neutron number	145
Relative Atomic Mass	245,075354 ± 0,00021 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	4,2 ± 1,3 s
spin	1/2
nuclear quadrupole moment	0
time of discovery or invention	1967
parity	+

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	7%
SF (spontaneous fission)	0.3%

²⁴⁶Fm

mass number	246
neutron number	146
Relative Atomic Mass	246,075353334 ± 0,000014675 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	1,54 ± 0,04 s
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1966
parity	+

decay mode	intensity
α (α emission)	93.2%
SF (spontaneous fission)	6.8%
ϵ (electron capture)	1.3%

²⁴⁷Fm

mass number	247
neutron number	147
Relative Atomic Mass	247,076944 ± 0,000194 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	31 ± 1 s
spin	7/2
nuclear quadrupole moment
time of discovery or invention	1967
parity	+

decay mode	intensity
α (α emission)	64%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

²⁴⁸Fm

mass number	248
neutron number	148
Relative Atomic Mass	248,077185451 ± 0,000009122 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	34,5 ± 1,2 s
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1958
parity	+

decay mode	intensity
α (α emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
SF (spontaneous fission)	0.1%

²⁴⁹Fm

mass number	249
neutron number	149
Relative Atomic Mass	249,078926042 ± 0,000006668 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	1,6 ± 0,1 m
spin	7/2
nuclear quadrupole moment
time of discovery or invention	1960
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)	33%

²⁵⁰Fm

mass number	250
neutron number	150
Relative Atomic Mass	250,079519765 ± 0,000008468 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	31 ± 1,1 m
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1954
parity	+

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	0.0069%
ϵ (electron capture)

²⁵¹Fm

mass number	251
neutron number	151
Relative Atomic Mass	251,08154513 ± 0,000015342 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	5,3 ± 0,08 h
spin	9/2
nuclear quadrupole moment
time of discovery or invention	1957
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	98.2%
α (α emission)	1.8%

²⁵²Fm

mass number	252
neutron number	152
Relative Atomic Mass	252,082466019 ± 0,000005604 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	25,39 ± 0,04 h
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1956
parity	+

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	0.0023%
2β⁺ (double β⁺ decay)

²⁵³Fm

mass number	253
neutron number	153
Relative Atomic Mass	253,085180945 ± 0,000001662 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	3 ± 0,12 d
spin	1/2
nuclear quadrupole moment	0
time of discovery or invention	1957
parity	+

decay mode	intensity
ϵ (electron capture)	88%
α (α emission)	12%

²⁵⁴Fm

mass number	254
neutron number	154
Relative Atomic Mass	254,086852424 ± 0,000001978 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	3,24 ± 0,002 h
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1954
parity	+

decay mode	intensity
α (α emission)	99.9408%
SF (spontaneous fission)	0.0592%

²⁵⁵Fm

mass number	255
neutron number	155
Relative Atomic Mass	255,089963495 ± 0,000004223 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	20,07 ± 0,07 h
spin	7/2
nuclear quadrupole moment
time of discovery or invention	1954
parity	+

decay mode	intensity
α (α emission)	100%
SF (spontaneous fission)	2.4%

²⁵⁶Fm

mass number	256
neutron number	156
Relative Atomic Mass	256,091771699 ± 0,000003241 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	157,1 ± 1,3 m
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1955
parity	+

decay mode	intensity
SF (spontaneous fission)	91.9%
α (α emission)	8.1%

²⁵⁷Fm

mass number	257
neutron number	157
Relative Atomic Mass	257,095105419 ± 0,000004669 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	100,5 ± 0,2 d
spin	9/2
nuclear quadrupole moment
time of discovery or invention	1964
parity	+

decay mode	intensity
α (α emission)	99.79%
SF (spontaneous fission)	0.21%

²⁵⁸Fm

mass number	258
neutron number	158
Relative Atomic Mass	258,097077 ± 0,000215 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life	370 ± 14 us
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1971
parity	+

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

²⁵⁹Fm

mass number	259
neutron number	159
Relative Atomic Mass	259,100596 ± 0,000304 Da
g-factor
natural abundance
radioactivity	☢️ radioactive element
half-life	1,5 ± 0,2 s
spin
nuclear quadrupole moment
time of discovery or invention	1980
parity

decay mode	intensity
SF (spontaneous fission)	100%

²⁶⁰Fm

mass number	260
neutron number	160
Relative Atomic Mass	260,102809 ± 0,000467 Da
g-factor	0
natural abundance
radioactivity	☢️ radioactive element
half-life
spin	0
nuclear quadrupole moment	0
time of discovery or invention
parity	+

decay mode	intensity
SF (spontaneous fission)

lisoló

discoverer or inventor	Argonne, Los Alamos, U of Calif
location of discovery	United States
time of discovery or invention	1953
etymology	Named in honor of the scientist Enrico Fermi.
pronunciation	FER-mi-em (lingɛlɛ́sa)

source

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

Nuclear Screening Constants

Femu on ChemicalAid

fermium

Australian Educational Vocabulary ID	scot/3519
CAS Registry Number	7440-72-4
ChEBI ID	33394
ChemSpider ID	22434
DSSTOX compound identifier	DTXCID60147884
DSSTox substance ID	DTXSID60225393
Den Store Danske ID	fermium
Encyclopædia Britannica Online ID	science/fermium
Encyclopædia Universalis ID	fermium
Freebase ID	/m/025rqck
GND ID	4490995-0
Gran Enciclopèdia Catalana ID	0108657
Great Russian Encyclopedia Online ID	4709674
InChI	InChI=1S/Fm
InChIKey	MIORUQGGZCBUGO-UHFFFAOYSA-N
KBpedia ID	Fermium
MeSH descriptor ID	D005286
OmegaWiki Defined Meaning	158627
PubChem CID	23998
Römpp online ID	RD-06-00507
Store norske leksikon ID	fermium
Treccani ID	fermio
UNII	Q70I3KBF4W
USGS Thesaurus ID	1453
WordNet 3.1 Synset ID	14661517-n

Femu (Fm)

Physical Property

Chemical Property

other

Isotopes of Fermium

241Fm

242Fm

243Fm

244Fm

245Fm

246Fm

247Fm

248Fm

249Fm

250Fm

251Fm

252Fm

253Fm

254Fm

255Fm

256Fm

257Fm

258Fm

259Fm

260Fm

lisoló

source

Nuclear Screening Constants

²⁴¹Fm

²⁴²Fm

²⁴³Fm

²⁴⁴Fm

²⁴⁵Fm

²⁴⁶Fm

²⁴⁷Fm

²⁴⁸Fm

²⁴⁹Fm

²⁵⁰Fm

²⁵¹Fm

²⁵²Fm

²⁵³Fm

²⁵⁴Fm

²⁵⁵Fm

²⁵⁶Fm

²⁵⁷Fm

²⁵⁸Fm

²⁵⁹Fm

²⁶⁰Fm