Curium (Cm)

Curium is the 96th element in the periodic table and has a symbol of Cm and atomic number of 96. It has an atomic weight of (247) and a mass number of 231. Curium has ninety-six protons and one hundred thirty-five neutrons in its nucleus, and ninety-six electrons in seven shells. It is located in group Actinides, period seven and block f of the periodic table. Radioactive metallic transuranic element. Belongs to actinoid series. Nine known isotopes, Cm-247 has a half-life of 1.64*10^7 years. First identified by Glenn T. Seaborg and associates in 1944, first produced by L.B. Werner and I. Perlman in 1947 by bombarding americium-241 with Neutrons. Named for Marie Curie.

Atomic Number	96
Atomic Weight	247
Mass Number	231

Group
Period	7
Block	f

Protons	96 p⁺
Neutrons	135 n⁰
Electrons	96 e^-

Physical Properties

Atomic Radius	276 pm
Molar Volume	18.28 cm³/mol
Covalent Radius	166 pm 136 pm 169 pm
Metallic Radius
Ionic Radius	97 pm 85 pm 95 pm 114.7 pm
Crystal Radius	111 pm 99 pm 109 pm 128.7 pm
Van der Waals Radius	245 pm 332.6 pm
Density	13.51 g/cm³

Chemical Properties

Energy

Proton Affinity
Electron Affinity
Ionization Energy	5.9914 eV/particle 10 eV/particle 20.1 eV/particle 37.7 eV/particle 51 eV/particle 69.1 eV/particle 97 eV/particle 112 eV/particle 128 eV/particle 144 eV/particle 167 eV/particle 190 eV/particle 212 eV/particle 235 eV/particle 253 eV/particle 272 eV/particle 311 eV/particle 332 eV/particle 460 eV/particle 489 eV/particle 518 eV/particle 550 eV/particle 580 eV/particle 611 eV/particle 657 eV/particle 689 eV/particle 723 eV/particle 755 eV/particle 910 eV/particle 950 eV/particle 990 eV/particle 1,030 eV/particle 1,140 eV/particle 1,180 eV/particle 1,300 eV/particle 1,340 eV/particle 1,480 eV/particle 1,560 eV/particle 1,640 eV/particle 1,730 eV/particle 1,810 eV/particle 1,890 eV/particle 1,980 eV/particle 2,060 eV/particle 2,160 eV/particle 2,240 eV/particle 2,320 eV/particle 2,410 eV/particle 2,490 eV/particle 2,580 eV/particle 2,976 eV/particle 3,050 eV/particle 3,125 eV/particle 3,207 eV/particle 3,284 eV/particle 3,360 eV/particle 3,515 eV/particle 3,593 eV/particle 3,679 eV/particle 3,758 eV/particle 4,078 eV/particle 4,156 eV/particle 4,239 eV/particle 4,317 eV/particle 4,791 eV/particle 4,880 eV/particle 5,110 eV/particle 5,200 eV/particle 8,270 eV/particle 8,440 eV/particle 8,620 eV/particle 8,820 eV/particle 9,000 eV/particle 9,180 eV/particle 9,630 eV/particle 9,820 eV/particle 10,020 eV/particle 10,220 eV/particle 10,760 eV/particle 10,920 eV/particle 11,100 eV/particle 11,270 eV/particle 12,740 eV/particle 12,950 eV/particle 13,360 eV/particle 13,550 eV/particle 27,740 eV/particle 28,180 eV/particle 28,700 eV/particle 29,100 eV/particle 34,600 eV/particle 35,200 eV/particle 36,000 eV/particle 36,493 eV/particle 143,299.6 eV/particle 145,743 eV/particle

Heat of Vaporization
Heat of Fusion
Heat of Formation	386 kJ/mol
Electrons

Electron Shells	2, 8, 18, 32, 25, 9, 2

Valence Electrons	2 ⓘ

Electron Configuration	[Rn] 5f⁷ 6d¹ 7s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 5f⁷ 6d¹ 7s²

Oxidation States	3, 4, 5, 6
Electronegativity	0.17439
Electrophilicity Index
States of Matter

Phase	Solid
Gas Phase
Boiling Point
Melting Point	1,618.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Curium is a Silver. Cm has a CPK of #ffffff, Jmol of #785ce3, and MOLCAS GV of #785ce3. The Appearance of Element 96 is silvery metallic, glows purple in the dark.
Color	Silver #ffffff #785ce3 #785ce3
Appearance	silvery metallic, glows purple in the dark
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type
Electrical Conductivity
Electrical Resistivity
Superconducting Point
Magnetism
Type
Magnetic Susceptibility (Mass)
Magnetic Susceptibility (Molar)
Magnetic Susceptibility (Volume)
Magnetic Ordering
Curie Point
Neel Point
Structure
The lattice angles of Curium are π/2, π/2, 2 π/3.
Crystal Structure	Simple Hexagonal ()
Lattice Constant
Lattice Angles	π/2, π/2, 2 π/3
Mechanical Properties

Hardness
Bulk Modulus
Shear Modulus
Young's Modulus
Poisson Ratio
Speed of Sound
Classification
The Glawe Number of Curium is 40. The Mendeleev Number of Cm is 28. The Pettifor Number of Element 96 is 41. The Goldschmidt Class of Curium (Cm) is synthetic.
Category	Actinides, Actinides
CAS Group
IUPAC Group
Glawe Number	40
Mendeleev Number	28
Pettifor Number	41
Geochemical Class
Goldschmidt Class	synthetic

Other

The Dipole Polarizability of Curium is 144 plus or minus 25 a₀. The Allotropes of Cm is . The Neutron Cross Section of Element 96 is 60. The Quantum Numbers of Curium (Cm) is 9D2. The Space Group of Curium is 194 (P63/mmc).

Gas Basicity
Dipole Polarizability	144 ± 25 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section	60
Neutron Mass Absorption
Quantum Numbers	9D2
Space Group	194 (P63/mmc)

Isotopes of Curium

Stable Isotopes	0
Unstable Isotopes	22
Natural Isotopes	0

²³¹Cm

Mass Number	231
Neutron Number	135
Relative Atomic Mass	231.050746 ± 0.000322 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	3/2
Quadrupole Moment
Discovery Year
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)

²³²Cm

Mass Number	232
Neutron Number	136
Relative Atomic Mass	232.04974 ± 0.000216 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)

²³³Cm

Mass Number	233
Neutron Number	137
Relative Atomic Mass	233.050771485 ± 0.000087059 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	27 ± 10 s
Spin	3/2
Quadrupole Moment
Discovery Year	2001
Parity	+

Decay Mode	Intensity
α (α emission)	20%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	80%

²³⁴Cm

Mass Number	234
Neutron Number	138
Relative Atomic Mass	234.050158568 ± 0.000018333 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	52 ± 9 s
Spin	0
Quadrupole Moment	0
Discovery Year	2001
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	71%
α (α emission)	27%
SF (spontaneous fission)	2%

²³⁵Cm

Mass Number	235
Neutron Number	139
Relative Atomic Mass	235.051545 ± 0.00011 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	7 ± 3 m
Spin	5/2
Quadrupole Moment
Discovery Year	1981
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)	4%

²³⁶Cm

Mass Number	236
Neutron Number	140
Relative Atomic Mass	236.051372112 ± 0.000018931 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	6.8 ± 0.8 m
Spin	0
Quadrupole Moment	0
Discovery Year	2010
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	82%
α (α emission)	18%
SF (spontaneous fission)

²³⁷Cm

Mass Number	237
Neutron Number	141
Relative Atomic Mass	237.052868988 ± 0.00007987 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	5/2
Quadrupole Moment
Discovery Year	2002
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
α (α emission)

²³⁸Cm

Mass Number	238
Neutron Number	142
Relative Atomic Mass	238.053081606 ± 0.000013133 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	2.2 ± 0.4 h
Spin	0
Quadrupole Moment	0
Discovery Year	1994
Parity	+

Decay Mode	Intensity
ϵ (electron capture)
α (α emission)	3.84%
SF (spontaneous fission)	0.048%

²³⁹Cm

Mass Number	239
Neutron Number	143
Relative Atomic Mass	239.054908519 ± 0.000161107 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	2.5 ± 0.4 h
Spin	7/2
Quadrupole Moment
Discovery Year	1952
Parity	-

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	6.2%

²⁴⁰Cm

Mass Number	240
Neutron Number	144
Relative Atomic Mass	240.055528233 ± 0.000002045 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	30.4 ± 3.7 d
Spin	0
Quadrupole Moment	0
Discovery Year	1949
Parity	+

Decay Mode	Intensity
α (α emission)	100%
ϵ (electron capture)
SF (spontaneous fission)	3.9%

²⁴¹Cm

Mass Number	241
Neutron Number	145
Relative Atomic Mass	241.057651218 ± 0.000001725 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	32.8 ± 0.2 d
Spin	1/2
Quadrupole Moment	0
Discovery Year	1952
Parity	+

Decay Mode	Intensity
ϵ (electron capture)	99%
α (α emission)	1%

²⁴²Cm

Mass Number	242
Neutron Number	146
Relative Atomic Mass	242.058834187 ± 0.000001224 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	162.8 ± 0.2 d
Spin	0
Quadrupole Moment	0
Discovery Year	1949
Parity	+

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	6.2%
34Si	1.1%
2β⁺ (double β⁺ decay)

²⁴³Cm

Mass Number	243
Neutron Number	147
Relative Atomic Mass	243.061387329 ± 0.000001605 Da
G-Factor	0.16 ± 0.032
Abundance
Radioactivity	☢️ Radioactive
Half Life	29.1 ± 0.1 y
Spin	5/2
Quadrupole Moment
Discovery Year	1950
Parity	+

Decay Mode	Intensity
α (α emission)	100%
ϵ (electron capture)	0.29%
SF (spontaneous fission)	5.3%

²⁴⁴Cm

Mass Number	244
Neutron Number	148
Relative Atomic Mass	244.062750622 ± 0.000001187 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	18.11 ± 0.03 y
Spin	0
Quadrupole Moment	0
Discovery Year	1950
Parity	+

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	1.37%

²⁴⁵Cm

Mass Number	245
Neutron Number	149
Relative Atomic Mass	245.065491047 ± 0.000001233 Da
G-Factor	0.14285714285714 ± 0.028571428571429
Abundance
Radioactivity	☢️ Radioactive
Half Life	8.25 ± 0.07 ky
Spin	7/2
Quadrupole Moment
Discovery Year	1954
Parity	+

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	6.1%

²⁴⁶Cm

Mass Number	246
Neutron Number	150
Relative Atomic Mass	246.067222016 ± 0.000001637 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	4.706 ± 0.04 ky
Spin	0
Quadrupole Moment	0
Discovery Year	1954
Parity	+

Decay Mode	Intensity
α (α emission)	99.97385%
SF (spontaneous fission)	0.02615%

²⁴⁷Cm

Mass Number	247
Neutron Number	151
Relative Atomic Mass	247.070352678 ± 0.000004076 Da
G-Factor	0.08 ± 0.015555555555556
Abundance
Radioactivity	☢️ Radioactive
Half Life	15.6 ± 0.5 My
Spin	9/2
Quadrupole Moment
Discovery Year	1954
Parity	-

Decay Mode	Intensity
α (α emission)	100%

²⁴⁸Cm

Mass Number	248
Neutron Number	152
Relative Atomic Mass	248.072349086 ± 0.000002531 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life	348 ± 6 ky
Spin	0
Quadrupole Moment	0
Discovery Year	1956
Parity	+

Decay Mode	Intensity
α (α emission)	91.61%
SF (spontaneous fission)	8.39%
2β⁻ (double β⁻ decay)

²⁴⁹Cm

Mass Number	249
Neutron Number	153
Relative Atomic Mass	249.075953992 ± 0.000002545 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	64.15 ± 0.03 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1956
Parity	+

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

²⁵⁰Cm

Mass Number	250
Neutron Number	154
Relative Atomic Mass	250.078357541 ± 0.000011029 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1966
Parity	+

Decay Mode	Intensity
SF (spontaneous fission)	74%
α (α emission)
β⁻ (β⁻ decay)

²⁵¹Cm

Mass Number	251
Neutron Number	155
Relative Atomic Mass	251.082284988 ± 0.000024367 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	16.8 ± 0.2 m
Spin	3/2
Quadrupole Moment
Discovery Year	1978
Parity	+

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

²⁵²Cm

Mass Number	252
Neutron Number	156
Relative Atomic Mass	252.08487 ± 0.00032 Da
G-Factor	0
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year
Parity	+

Decay Mode	Intensity
β⁻ (β⁻ decay)
α (α emission)

History

Curium was discovered by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso in 1944 at the University of California, Berkeley. It was produced by bombarding plutonium with alpha particles during the Manhattan Project. Curium metal was produced only in 1951 by reduction of curium fluoride with barium. Curium is named after Madame Curie and her husband Pierre Curie

Discoverers	G.T.Seaborg, R.A.James, A.Ghiorso
Discovery Location	United States
Discovery Year	1944
Etymology (Name Origin)	Named in honor of Pierre and Marie Curie.
Pronunciation	KYOOR-i-em (English)

Curium is harmful due to its radioactivity

Curium accumulates in the bones, lungs and liver, where it promotes cancer

Uses

Curium is mainly used for scientific research purposes. Curium is a common starting material for the production of higher transuranic elements and transactinides. The most practical application of ²⁴⁴Cm is as α-particle source in the alpha particle X-ray spectrometers (APXS). It has no significant commercial applications.

Sources

Made by bombarding plutonium with helium ions. So radioactive it glows in the dark.

Abundance
Abundance in Earth's crust
Natural Abundance (Oceans)
Natural Abundance (Human Body)	0 %
Natural Abundance (Meteor)	0 %
Natural Abundance (Sun)	0 %
Abundance in Universe	0 %

Nuclear Screening Constants

Also Known As

Cm
element 96

Translations

Frenchcurium
Norwegian Bokmålcurium
GermanCurium
Amharicኩሪየም
Arabicكوريوم
AzerbaijaniKürium
BelarusianКюрый
Banglaকুরিয়াম
Bosniankirij
Catalancuri
CorsicanCuriu
Czechcurium
ChuvashКюри
WelshCuriwm
Danishcurium
Greekκιούριο
Esperantokuriumo
Spanishcurio
Estoniankuurium
Basquekurio
Persianکوریم
Finnishcurium
FriulianCuri
Irishciúiriam
Galiciancurio
ManxCurium
Hakka Chinesecurium
Hebrewקוריום
Croatiankirij
Hungariankűrium
Armenianկյուրիում
Interlinguacurium
Indonesiankurium
Idokuriumo
Italiancurio
Japaneseキュリウム
Lojbanjinmrkuri
JavaneseKurium
Kannadaಕ್ಯೂರಿಯಮ್
Korean퀴륨
KomiКюрий
Latincurium
LuxembourgishCurium
LigurianCurio
Lithuaniankiuris
Latviankirijs
Malayalamക്യൂറിയം
Marathiक्युरियम
MalayKurium
Burmeseကျူရီယမ်
Dutchcurium
Norwegian Nynorskcurium
Polishkiur
Portuguesecúrio
QuechuaKuriyu
Romaniancuriu
Russianкюрий
YakutКүриум
Siciliancuriu
Serbo-CroatianKirijum
Slovakcurium
Sloveniankirij
Albaniancuriumi
Serbianкиријум
Saterland FrisianCurium
Swedishcurium
Swahilicuri
Tamilகியூரியம்
Thaiคูเรียม
Turkishküriyum
Uyghurكىيۇرىي
Ukrainianкюрій
Urduکیوریئم
VepsKürii
Vietnamesecuri
WarayCuryo
KalmykКүриүм
YorubaKùríọ̀m
Chinese锔
English (United Kingdom)curium
CebuanoKuryo
Macedonianкириум
Central Kurdishکوریۆم
Western Panjabiکیوریم
BretonKuriom
Gujaratiક્યુરીયમ
Odiaକ୍ୟୁରିଅମ
Occitancurium
PiedmonteseCurio
TatarКюрий
Bulgarianкюрий
Fiji HindiCurium
Western MariКӱрий
Hindiक्यूरियम
Newariक्युरियम
Cantonese鋦
KazakhКюрий
Belarusian (Taraskievica orthography)Кюр
AromanianCuriu
Nepaliक्युरियम
KyrgyzКюрий
LimburgishCurium
FaroeseCurium
Sanskritक्युरियम
Teluguక్యూరియం
Maltesekurju
Scottish GaelicCurium
Paliक्युरियम
cdoCurium
Min Nan ChineseCurium
AsturianCurio
UzbekKyuriy
Bhojpuriक्युरियम
Chinese (Traditional)鋦
Chinese (Macao SAR China)鋦
Chinese (China)锔
Chinese (Simplified)锔
Chinese (Hong Kong SAR China)鋦
Chinese (Malaysia)锔
Chinese (Singapore)锔
Chinese (Taiwan)鋦
Portuguese (Brazil)cúrio
Lingua Franca Novacurio
TagalogKuryo
AfrikaansCurium
kbpKʊrɩyɔm
Northern FrisianKuurium
Literary Chinese鋦
Volapükkurin
oloK’urii
Mongolianкюри
TajikКюрий
Georgianკიურიუმი
Wu Chinese锔
SardinianCùriu
BashkirКюрий
Moroccan Arabicكوريوم
Egyptian Arabicكوريوم
Pashtoکيوريوم
CornishKuriom
Manipuriꯀ꯭ꯌꯨꯔꯤꯌꯝ
BalineseCurium
ZuluIChumumbi

Curium on ChemicalAid

Australian Educational Vocabulary ID	scot/3513
CAB ID	7536
CAS Registry Number	7440-51-9
Catholic Encyclopedia ID	04572c
ChEBI ID	33390
ChemSpider ID	22415
DSSTOX compound identifier	DTXCID80147881
DSSTox substance ID	DTXSID80225390
Den Store Danske ID	curium
Encyclopædia Britannica Online ID	science/curium-chemical-element
Encyclopædia Universalis ID	curium
Freebase ID	/m/025tkv0
French Vikidia ID	Curium
GND ID	4148404-6
Great Russian Encyclopedia Online ID	2127358
InChI	InChI=1S/Cm
InChIKey	NIWWFAAXEMMFMS-UHFFFAOYSA-N
KBpedia ID	Curium
Library of Congress authority ID	sh85034863
MeSH descriptor ID	D003476
NALT ID	3199
NDL Authority ID	00575294
National Library of Israel J9U ID	987007538486405171
OmegaWiki Defined Meaning	157032
OpenAlex ID	C555352317
PDB ligand ID	ZCM
PDB structure ID	4ZHF
PubChem CID	23979
Quora topic ID	Curium
Römpp online ID	RD-03-02962
Store norske leksikon ID	curium
Treccani ID	curio
UNII	M5LL84MZ2W
USGS Thesaurus ID	1438
WordNet 3.1 Synset ID	14660398-n

Curium (Cm)

Physical Properties

Chemical Properties

Other

Isotopes of Curium

231Cm

232Cm

233Cm

234Cm

235Cm

236Cm

237Cm

238Cm

239Cm

240Cm

241Cm

242Cm

243Cm

244Cm

245Cm

246Cm

247Cm

248Cm

249Cm

250Cm

251Cm

252Cm