Radium

Radium (Ra)

Radioactive metallic transuranic element, belongs to group 2 of the periodic table. Most stable isotope, Ra-226 has a half-life of 1602 years, which decays into radon. Isolated from pitchblende in 1898 Marie and Pierre Curie.
Atomic Number88
Atomic Weight226
Mass Number201
Group2
Period7
Blocks
Protons88 p+
Neutrons113 n0
Electrons88 e-
Radium226.jpg Animated Bohr Model of Ra (Radium) Enhanced Bohr Model of Ra (Radium) Bohr Model: Ra (Radium) Orbital Diagram of Ra (Radium)

Properties

Atomic Radius
215 pm
Molar Volume
Covalent Radius
201 pm
Metallic Radius
Ionic Radius
148 pm
Crystal Radius
162 pm
Van der Waals Radius
283 pm
Density
Energy
Proton Affinity
Electron Affinity
Ionization Energy
5.278424 eV/particle
Heat of Vaporization
113 kJ/mol
Heat of Fusion
9.6 kJ/mol
Heat of Formation
159 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 18, 8, 2
Valence Electrons2
Electron Configuration[Rn] 7s2
Oxidation States2
Electronegativity
0.9
Electrophilicity
0.6982685447294388 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
Melting Point
969.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearancesilvery white metallic
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
1 MS/m
Electrical Resistivity
0.000001 m Ω
Superconducting Point
Magnetism
Type
Magnetic Susceptibility (Mass)
Magnetic Susceptibility (Molar)
Magnetic Susceptibility (Volume)
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureBody Centered Cubic ()
Lattice Constant
Lattice Anglesπ/2, π/2, π/2
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
CategoryAlkaline earth metals, Alkaline earth metals
CAS GroupIIA
IUPAC GroupIIA
Glawe Number13
Mendeleev Number10
Pettifor Number13
Geochemical ClassU/Th decay series
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
246 ± 4 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
13
Neutron Mass Absorption
Quantum Numbers1S0
Space Group229 (Im_3m)

Isotopes of Radium

Stable Isotopes0
Unstable Isotopes35
Radioactive Isotopes35

201Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
201.012814699 ± 0.000021794 Da
Mass Number201
G-Factor
Half Life
20 ± 30 ms
Spin3/2
Quadrupole Moment
Discovery Year2005
Parity-

201Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

202Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
202.009742305 ± 0.000016122 Da
Mass Number202
G-Factor
0
Half Life
4.1 ± 1.1 ms
Spin0
Quadrupole Moment
0
Discovery Year2005
Parity+

202Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

203Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
203.009233907 ± 0.0000104 Da
Mass Number203
G-Factor
Half Life
36 ± 13 ms
Spin3/2
Quadrupole Moment
Discovery Year1996
Parity-

203Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

204Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
204.006506855 ± 0.00000958 Da
Mass Number204
G-Factor
0
Half Life
60 ± 9 ms
Spin0
Quadrupole Moment
0
Discovery Year1995
Parity+

204Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

205Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
205.006230692 ± 0.000024446 Da
Mass Number205
G-Factor
Half Life
220 ± 50 ms
Spin3/2
Quadrupole Moment
Discovery Year1987
Parity-

205Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

206Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
206.003827842 ± 0.000019332 Da
Mass Number206
G-Factor
0
Half Life
240 ± 20 ms
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

206Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

207Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
207.00377242 ± 0.000062572 Da
Mass Number207
G-Factor
Half Life
1.38 ± 0.18 s
Spin5/2
Quadrupole Moment
Discovery Year1967
Parity-

207Ra Decay Modes
Decay ModeIntensity
α (α emission)86%
β+ (β+ decay; β+ = ϵ + e+)%

208Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
208.001855012 ± 0.000009686 Da
Mass Number208
G-Factor
0
Half Life
1.11 ± 0.045 s
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

208Ra Decay Modes
Decay ModeIntensity
α (α emission)87%
β+ (β+ decay; β+ = ϵ + e+)%

209Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
209.001994902 ± 0.000006169 Da
Mass Number209
G-Factor
0.3444 ± 0.0052
Half Life
4.71 ± 0.08 s
Spin5/2
Quadrupole Moment
0.39 ± 0.04
Discovery Year1967
Parity-

209Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

210Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
210.000475406 ± 0.000009868 Da
Mass Number210
G-Factor
0
Half Life
4 ± 0.1 s
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

210Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

211Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
211.000893049 ± 0.000005331 Da
Mass Number211
G-Factor
0.3496 ± 0.0016
Half Life
12.6 ± 1.2 s
Spin5/2
Quadrupole Moment
0.46 ± 0.04
Discovery Year1967
Parity-

211Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

212Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
211.999786619 ± 0.000011007 Da
Mass Number212
G-Factor
0
Half Life
13 ± 0.2 s
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

212Ra Decay Modes
Decay ModeIntensity
α (α emission)%
β+ (β+ decay; β+ = ϵ + e+)%

213Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
213.000370971 ± 0.00001054 Da
Mass Number213
G-Factor
1.22 ± 0.004
Half Life
2.73 ± 0.05 m
Spin1/2
Quadrupole Moment
0
Discovery Year1955
Parity-

213Ra Decay Modes
Decay ModeIntensity
α (α emission)87%
β+ (β+ decay; β+ = ϵ + e+)13%

214Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
214.00009956 ± 0.000005636 Da
Mass Number214
G-Factor
0
Half Life
2.437 ± 0.016 s
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

214Ra Decay Modes
Decay ModeIntensity
α (α emission)99.941%
β+ (β+ decay; β+ = ϵ + e+)0.059%

215Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
215.002718208 ± 0.00000773 Da
Mass Number215
G-Factor
Half Life
1.669 ± 0.009 ms
Spin9/2
Quadrupole Moment
Discovery Year1967
Parity+

215Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

216Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
216.003533534 ± 0.000008592 Da
Mass Number216
G-Factor
0
Half Life
172 ± 7 ns
Spin0
Quadrupole Moment
0
Discovery Year1972
Parity+

216Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
ϵ (electron capture)1%

217Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
217.006322676 ± 0.000007564 Da
Mass Number217
G-Factor
Half Life
1.95 ± 0.12 us
Spin9/2
Quadrupole Moment
Discovery Year1970
Parity+

217Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

218Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
218.007134297 ± 0.000010528 Da
Mass Number218
G-Factor
0
Half Life
25.91 ± 0.14 us
Spin0
Quadrupole Moment
0
Discovery Year1970
Parity+

218Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

219Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
219.010084715 ± 0.000007315 Da
Mass Number219
G-Factor
Half Life
9 ± 2 ms
Spin7/2
Quadrupole Moment
Discovery Year1952
Parity

219Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

220Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
220.011027542 ± 0.000008153 Da
Mass Number220
G-Factor
0
Half Life
18.1 ± 1.2 ms
Spin0
Quadrupole Moment
0
Discovery Year1949
Parity+

220Ra Decay Modes
Decay ModeIntensity
α (α emission)100%

221Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
221.013917293 ± 0.00000497 Da
Mass Number221
G-Factor
-0.0716 ± 0.00068
Half Life
25 ± 4 s
Spin5/2
Quadrupole Moment
1.92 ± 0.06
Discovery Year1949
Parity+

221Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
14C1.2%

222Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
222.015373371 ± 0.000004781 Da
Mass Number222
G-Factor
0
Half Life
33.6 ± 0.4 s
Spin0
Quadrupole Moment
0
Discovery Year1948
Parity+

222Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
14C3%

223Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
223.018500648 ± 0.000002243 Da
Mass Number223
G-Factor
0.17946666666667 ± 0.00053333333333333
Half Life
11.4352 ± 0.001 d
Spin3/2
Quadrupole Moment
1.22 ± 0.03
Discovery Year1905
Parity+

223Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
14C8.9%

224Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
224.020210361 ± 0.000001944 Da
Mass Number224
G-Factor
0
Half Life
3.6316 ± 0.0014 d
Spin0
Quadrupole Moment
0
Discovery Year1902
Parity+

224Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
14C4%

225Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
225.023610502 ± 0.000002786 Da
Mass Number225
G-Factor
-1.46 ± 0.004
Half Life
14.82 ± 0.19 d
Spin1/2
Quadrupole Moment
0
Discovery Year1947
Parity+

225Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

226Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
226.025408186 ± 0.000002068 Da
Mass Number226
G-Factor
0
Half Life
1.6 ± 0.007 ky
Spin0
Quadrupole Moment
0
Discovery Year1898
Parity+

226Ra Decay Modes
Decay ModeIntensity
α (α emission)100%
14C2.6%
(double β decay)%

227Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
227.029176205 ± 0.000002089 Da
Mass Number227
G-Factor
-0.26733333333333 ± 0.00073333333333333
Half Life
42.2 ± 0.5 m
Spin3/2
Quadrupole Moment
1.53 ± 0.06
Discovery Year1953
Parity+

227Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

228Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
228.031068574 ± 0.000002141 Da
Mass Number228
G-Factor
0
Half Life
5.75 ± 0.03 y
Spin0
Quadrupole Moment
0
Discovery Year1907
Parity+

228Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

229Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
229.034956703 ± 0.000016576 Da
Mass Number229
G-Factor
0.19968 ± 0.00056
Half Life
4 ± 0.2 m
Spin5/2
Quadrupole Moment
2.99 ± 0.12
Discovery Year1975
Parity+

229Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

230Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
230.037054776 ± 0.000011053 Da
Mass Number230
G-Factor
0
Half Life
93 ± 2 m
Spin0
Quadrupole Moment
0
Discovery Year1978
Parity+

230Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

231Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
231.041027085 ± 0.000012206 Da
Mass Number231
G-Factor
-0.14216 ± 0.00044
Half Life
104 ± 1 s
Spin5/2
Quadrupole Moment
Discovery Year1983
Parity+

231Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

232Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
232.043475267 ± 0.000009823 Da
Mass Number232
G-Factor
0
Half Life
4 ± 0.3 m
Spin0
Quadrupole Moment
0
Discovery Year1983
Parity+

232Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

233Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
233.04759457 ± 0.000009235 Da
Mass Number233
G-Factor
Half Life
30 ± 5 s
Spin1/2
Quadrupole Moment
0
Discovery Year1990
Parity+

233Ra Decay Modes
Decay ModeIntensity
β (β decay)100%

234Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
234.0503821 ± 0.000009 Da
Mass Number234
G-Factor
0
Half Life
30 ± 10 s
Spin0
Quadrupole Moment
0
Discovery Year1990
Parity+

234Ra Decay Modes
Decay ModeIntensity
β (β decay)100%
β SF (β-delayed fission)%

235Ra

AbundanceRadioactive ☢️
Relative Atomic Mass
235.05489 ± 0.000322 Da
Mass Number235
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year
Parity+

235Ra Decay Modes
Decay ModeIntensity
β (β decay)%

History

Radium was discovered by Marie Curie and Pierre Curie in 1898. They extracted the radium compound from a uraninite sample. Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne in 1910 through the electrolysis of radium chloride by using a mercury cathode and distilling in an atmosphere of hydrogen gas. From the Latin word radius meaning ray

DiscoverersPierre and Marie Curie
Discovery LocationFrance
Discovery Year1898
Etymology (Name Origin)Latin: radius (ray).
PronunciationRAY-di-em (English)
Radium is highly radioactive and carcinogenic
Radium imparts a carmine red color to a flame

Uses

Radium was formerly used in self-luminous paints for watches, nuclear panels, aircraft switches, clocks, and instrument dials. Radium chloride was used in medicine to produce radon gas which in turn was used as a cancer treatment. The isotope 223Ra is currently under investigation for use in medicine as a cancer treatment of bone metastasis. Used in treating cancer because of the gamma rays it gives off.

Sources

Found in uranium ores at 1 part per 3 million parts uranium.

Abundance
Abundance in Earth's crust
0.0000009 mg/kg
Abundance in Oceans
0.000000000089 mg/L
Abundance in Human Body
0.0000000000001 %
Abundance in Meteor
Abundance in Sun
Abundance in Universe
0 %

Nuclear Screening Constants