Lanthanum

Lanthanum (La)

(From the Greek word lanthanein, to line hidden) Silvery metallic element belonging to group 3 of the periodic table and oft considered to be one of the lanthanoids. Found in some rare-earth minerals. Twenty-five natural isotopes exist. La-139 which is stable, and La-138 which has a half-life of 10^10 to 10^15 years. The other twenty-three isotopes are radioactive. It resembles the lanthanoids chemically. Lanthanum has a low to moderate level of toxicity, and should be handled with care. Discovered in 1839 by C.G. Mosander.
Atomic Number57
Atomic Weight138.90547
Mass Number139
Group3
Period6
Blockd
Protons57 p+
Neutrons82 n0
Electrons57 e-
Lanthan 1-cropflipped.jpg Animated Bohr Model of La (Lanthanum) Enhanced Bohr Model of La (Lanthanum) Bohr Model: La (Lanthanum) Orbital Diagram of La (Lanthanum)

Properties

Atomic Radius
195 pm
Molar Volume
Covalent Radius
180 pm
Metallic Radius
169 pm
Ionic Radius
103.2 pm
Crystal Radius
117.2 pm
Van der Waals Radius
243 pm
Density
6.15 g/cm³
Energy
Proton Affinity
1,013 kJ/mol
Electron Affinity
Ionization Energy
Heat of Vaporization
402 kJ/mol
Heat of Fusion
8.5 kJ/mol
Heat of Formation
431 kJ/mol
Electrons
Electron Shells2, 8, 18, 18, 9, 2
Valence Electrons3
Electron Configuration[Xe] 5d1 6s2
Oxidation States0, 1, 2, 3
Electronegativity
1.1
Electrophilicity
0.894990101871977 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
3,737.15 K
Melting Point
1,193.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearancesilvery white
Refractive Index
Thermodynamic Properties
Thermal Conductivity
13.4 W/(m K)
Thermal Expansion
0.0000121 1/K
Molar Heat Capacity
27.11 J/(mol K)
Specific Heat Capacity
0.195 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
1.6 MS/m
Electrical Resistivity
0.00000061 m Ω
Superconducting Point
4.88 K
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.000000011 m³/Kg
Magnetic Susceptibility (Molar)
0.000000001528 m³/mol
Magnetic Susceptibility (Volume)
0.00006761
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.75 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
2.5 MPa
Bulk Modulus
28 GPa
Shear Modulus
14 GPa
Young Modulus
37 GPa
Poisson Ratio
0.28
Speed of Sound
2,475 m/s
Classification
CategoryLanthanides, Lanthanides
CAS GroupIIIA
IUPAC GroupIIIB
Glawe Number32
Mendeleev Number13
Pettifor Number33
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Other
Gas Basicity
991.9 kJ/mol
Dipole Polarizability
215 ± 20 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
8.98
Neutron Mass Absorption
0.0023
Quantum Numbers2D3/2
Space Group194 (P63/mmc)

Isotopes of Lanthanum

Stable Isotopes2
Unstable Isotopes40
Radioactive Isotopes41

116La

AbundanceRadioactive ☢️
Relative Atomic Mass
115.957005 ± 0.000345 Da
Mass Number116
G-Factor
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

116La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%
p (proton emission)%

117La

AbundanceRadioactive ☢️
Relative Atomic Mass
116.950326 ± 0.000215 Da
Mass Number117
G-Factor
Half Life
21.7 ± 1.8 ms
Spin3/2
Quadrupole Moment
Discovery Year2001
Parity+

117La Decay Modes
Decay ModeIntensity
p (proton emission)100%
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

118La

AbundanceRadioactive ☢️
Relative Atomic Mass
117.946731 ± 0.000322 Da
Mass Number118
G-Factor
Half Life
Spin1
Quadrupole Moment
Discovery Year
Parity-

118La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

119La

AbundanceRadioactive ☢️
Relative Atomic Mass
118.940934 ± 0.000322 Da
Mass Number119
G-Factor
Half Life
Spin11/2
Quadrupole Moment
Discovery Year
Parity-

119La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%

120La

AbundanceRadioactive ☢️
Relative Atomic Mass
119.938196 ± 0.000322 Da
Mass Number120
G-Factor
Half Life
2.8 ± 0.2 s
Spin1
Quadrupole Moment
Discovery Year1984
Parity-

120La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

121La

AbundanceRadioactive ☢️
Relative Atomic Mass
120.933236 ± 0.000322 Da
Mass Number121
G-Factor
Half Life
5.3 ± 0.2 s
Spin11/2
Quadrupole Moment
Discovery Year1988
Parity-

121La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

122La

AbundanceRadioactive ☢️
Relative Atomic Mass
121.93071 ± 0.00032 Da
Mass Number122
G-Factor
Half Life
8.6 ± 0.5 s
Spin1
Quadrupole Moment
Discovery Year1984
Parity-

122La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

123La

AbundanceRadioactive ☢️
Relative Atomic Mass
122.9263 ± 0.00021 Da
Mass Number123
G-Factor
Half Life
17 ± 3 s
Spin11/2
Quadrupole Moment
Discovery Year1978
Parity-

123La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

124La

AbundanceRadioactive ☢️
Relative Atomic Mass
123.924574275 ± 0.000060836 Da
Mass Number124
G-Factor
Half Life
29.21 ± 0.17 s
Spin7
Quadrupole Moment
Discovery Year1978
Parity

124La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

125La

AbundanceRadioactive ☢️
Relative Atomic Mass
124.920815931 ± 0.000027909 Da
Mass Number125
G-Factor
Half Life
64.8 ± 1.2 s
Spin11/2
Quadrupole Moment
Discovery Year1973
Parity-

125La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

126La

AbundanceRadioactive ☢️
Relative Atomic Mass
125.919512667 ± 0.000097163 Da
Mass Number126
G-Factor
Half Life
54 ± 2 s
Spin5
Quadrupole Moment
Discovery Year1961
Parity-

126La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

127La

AbundanceRadioactive ☢️
Relative Atomic Mass
126.916375083 ± 0.000027912 Da
Mass Number127
G-Factor
Half Life
5.1 ± 0.1 m
Spin11/2
Quadrupole Moment
Discovery Year1963
Parity-

127La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

128La

AbundanceRadioactive ☢️
Relative Atomic Mass
127.915592123 ± 0.000058452 Da
Mass Number128
G-Factor
Half Life
5.18 ± 0.14 m
Spin5
Quadrupole Moment
Discovery Year1961
Parity+

128La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

129La

AbundanceRadioactive ☢️
Relative Atomic Mass
128.912695592 ± 0.000022913 Da
Mass Number129
G-Factor
Half Life
11.6 ± 0.2 m
Spin3/2
Quadrupole Moment
Discovery Year1963
Parity+

129La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

130La

AbundanceRadioactive ☢️
Relative Atomic Mass
129.912369413 ± 0.000027854 Da
Mass Number130
G-Factor
Half Life
8.7 ± 0.1 m
Spin3
Quadrupole Moment
Discovery Year1961
Parity

130La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

131La

AbundanceRadioactive ☢️
Relative Atomic Mass
130.91007 ± 0.00003 Da
Mass Number131
G-Factor
Half Life
59 ± 2 m
Spin3/2
Quadrupole Moment
Discovery Year1951
Parity+

131La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

132La

AbundanceRadioactive ☢️
Relative Atomic Mass
131.910119047 ± 0.000039032 Da
Mass Number132
G-Factor
Half Life
4.59 ± 0.04 h
Spin2
Quadrupole Moment
Discovery Year1951
Parity-

132La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

133La

AbundanceRadioactive ☢️
Relative Atomic Mass
132.908218 ± 0.00003 Da
Mass Number133
G-Factor
Half Life
3.912 ± 0.008 h
Spin5/2
Quadrupole Moment
Discovery Year1950
Parity+

133La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

134La

AbundanceRadioactive ☢️
Relative Atomic Mass
133.908514011 ± 0.000021395 Da
Mass Number134
G-Factor
Half Life
6.45 ± 0.16 m
Spin1
Quadrupole Moment
Discovery Year1951
Parity+

134La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

135La

AbundanceRadioactive ☢️
Relative Atomic Mass
134.906984427 ± 0.000010126 Da
Mass Number135
G-Factor
1.48 ± 0.036
Half Life
18.91 ± 0.02 h
Spin5/2
Quadrupole Moment
-0.4 ± 0.4
Discovery Year1948
Parity+

135La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

136La

AbundanceRadioactive ☢️
Relative Atomic Mass
135.907634962 ± 0.000057081 Da
Mass Number136
G-Factor
Half Life
9.87 ± 0.03 m
Spin1
Quadrupole Moment
Discovery Year1950
Parity+

136La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

137La

AbundanceRadioactive ☢️
Relative Atomic Mass
136.906450438 ± 0.00000176 Da
Mass Number137
G-Factor
0.77028571428571 ± 0.0017142857142857
Half Life
60 ± 20 ky
Spin7/2
Quadrupole Moment
0.21 ± 0.04
Discovery Year1948
Parity+

137La Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

138La

AbundanceRadioactive ☢️
0.08881 ± 0.00071
Relative Atomic Mass
137.907124041 ± 0.000000446 Da
Mass Number138
G-Factor
0.74168 ± 0.00004
Half Life
103 ± 1 Gy
Spin5
Quadrupole Moment
0.39 ± 0.03
Discovery Year1947
Parity+

138La Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)65.5%
β (β decay)34.5%

139La

Abundance
99.91119 ± 0.00071
Relative Atomic Mass
138.906362927 ± 0.000000651 Da
Mass Number139
G-Factor
0.79402857142857 ± 0.000057142857142857
Half Life
Spin7/2
Quadrupole Moment
0.206 ± 0.004
Discovery Year1924
Parity+

140La

AbundanceRadioactive ☢️
Relative Atomic Mass
139.909487285 ± 0.000000651 Da
Mass Number140
G-Factor
0.24333333333333 ± 0.005
Half Life
40.289 ± 0.004 h
Spin3
Quadrupole Moment
0.087 ± 0.013
Discovery Year1935
Parity-

140La Decay Modes
Decay ModeIntensity
β (β decay)100%

141La

AbundanceRadioactive ☢️
Relative Atomic Mass
140.910971155 ± 0.00000443 Da
Mass Number141
G-Factor
Half Life
3.92 ± 0.03 h
Spin7/2
Quadrupole Moment
Discovery Year1951
Parity+

141La Decay Modes
Decay ModeIntensity
β (β decay)100%

142La

AbundanceRadioactive ☢️
Relative Atomic Mass
141.91409076 ± 0.000006748 Da
Mass Number142
G-Factor
Half Life
91.1 ± 0.5 m
Spin2
Quadrupole Moment
Discovery Year1953
Parity-

142La Decay Modes
Decay ModeIntensity
β (β decay)100%

143La

AbundanceRadioactive ☢️
Relative Atomic Mass
142.916079482 ± 0.000007868 Da
Mass Number143
G-Factor
Half Life
14.2 ± 0.1 m
Spin7/2
Quadrupole Moment
Discovery Year1951
Parity

143La Decay Modes
Decay ModeIntensity
β (β decay)100%

144La

AbundanceRadioactive ☢️
Relative Atomic Mass
143.919645589 ± 0.000013888 Da
Mass Number144
G-Factor
Half Life
44 ± 0.7 s
Spin3
Quadrupole Moment
Discovery Year1967
Parity-

144La Decay Modes
Decay ModeIntensity
β (β decay)100%

145La

AbundanceRadioactive ☢️
Relative Atomic Mass
144.921808065 ± 0.00001317 Da
Mass Number145
G-Factor
Half Life
24.8 ± 2 s
Spin5/2
Quadrupole Moment
Discovery Year1974
Parity+

145La Decay Modes
Decay ModeIntensity
β (β decay)100%

146La

AbundanceRadioactive ☢️
Relative Atomic Mass
145.925688017 ± 0.000001797 Da
Mass Number146
G-Factor
Half Life
9.9 ± 0.1 s
Spin5
Quadrupole Moment
Discovery Year1970
Parity-

146La Decay Modes
Decay ModeIntensity
β (β decay)100%

147La

AbundanceRadioactive ☢️
Relative Atomic Mass
146.9284178 ± 0.0000115 Da
Mass Number147
G-Factor
Half Life
4.026 ± 0.02 s
Spin5/2
Quadrupole Moment
Discovery Year1979
Parity+

147La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.041%

148La

AbundanceRadioactive ☢️
Relative Atomic Mass
147.9326794 ± 0.0000209 Da
Mass Number148
G-Factor
Half Life
1.414 ± 0.025 s
Spin2
Quadrupole Moment
Discovery Year1969
Parity-

148La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.18%

149La

AbundanceRadioactive ☢️
Relative Atomic Mass
148.935351259 ± 0.00021499 Da
Mass Number149
G-Factor
Half Life
1.071 ± 0.022 s
Spin3/2
Quadrupole Moment
Discovery Year1979
Parity-

149La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)1.43%

150La

AbundanceRadioactive ☢️
Relative Atomic Mass
149.9395475 ± 0.0000027 Da
Mass Number150
G-Factor
Half Life
504 ± 15 ms
Spin3
Quadrupole Moment
Discovery Year1993
Parity+

150La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)2.7%

151La

AbundanceRadioactive ☢️
Relative Atomic Mass
150.942769 ± 0.0004675 Da
Mass Number151
G-Factor
Half Life
465 ± 24 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1994
Parity+

151La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

152La

AbundanceRadioactive ☢️
Relative Atomic Mass
151.947085 ± 0.000322 Da
Mass Number152
G-Factor
Half Life
287 ± 16 ms
Spin2
Quadrupole Moment
Discovery Year1994
Parity-

152La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

153La

AbundanceRadioactive ☢️
Relative Atomic Mass
152.950553 ± 0.000322 Da
Mass Number153
G-Factor
Half Life
245 ± 18 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1994
Parity+

153La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

154La

AbundanceRadioactive ☢️
Relative Atomic Mass
153.955416 ± 0.000322 Da
Mass Number154
G-Factor
Half Life
161 ± 15 ms
Spin2
Quadrupole Moment
Discovery Year2017
Parity-

154La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

155La

AbundanceRadioactive ☢️
Relative Atomic Mass
154.95928 ± 0.000429 Da
Mass Number155
G-Factor
Half Life
101 ± 28 ms
Spin1/2
Quadrupole Moment
0
Discovery Year2016
Parity+

155La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

156La

AbundanceRadioactive ☢️
Relative Atomic Mass
155.964519 ± 0.000429 Da
Mass Number156
G-Factor
Half Life
84 ± 78 ms
Spin4
Quadrupole Moment
Discovery Year2017
Parity+

156La Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

157La

AbundanceRadioactive ☢️
Relative Atomic Mass
156.968792 ± 0.000322 Da
Mass Number157
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2018
Parity+

157La Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

History

Lanthanum was discovered in 1839 by Swedish chemist Carl Gustav Mosander. He partially decomposed a sample of cerium nitrate by heating and treating the resulting salt with dilute nitric acid. From the resulting solution, he obtained a pale brick colored oxide of the new rare earth. Lanthanum was isolated in relatively pure form in 1923. From the Greek word lanthanein, to lie hidden

DiscoverersCarl Mosander
Discovery LocationSweden
Discovery Year1839
Etymology (Name Origin)Greek: lanthanein (to be hidden).
PronunciationLAN-the-nem (English)
Lanthanum and its compounds are considered to be moderately toxic
Lanthanum is the most reactive of the rare earth metals

Uses

Lanthanum is used in large quantities in batteries for hybrid automobiles. It is also used to make night vision goggles. Small amounts of lanthanum, as an additive, can be used to produce nodular cast iron. Lanthanum carbonate is used to reduce blood levels of phosphate in patients with kidney disease. It is used in the electodes of high-intensity, carbon-arc lights. Also used in the production of high-grade europium metal. Because it gives glass refractive properties, it is used in expensive camera lenses.

Sources

Found with rare earths in monazite and bastnasite. Monazite sand typicall contains 25% lanthanum.

Abundance
Abundance in Earth's crust
Abundance in Oceans
0.0000034 mg/L
Abundance in Human Body
Abundance in Meteor
0.000028 %
Abundance in Sun
0.0000002 %
Abundance in Universe
0.0000002 %

Nuclear Screening Constants

1s1.1317
2p4.2044
2s15.0466
3d13.9398
3p18.8604
3s19.0569
4d32.2748
4f55.64
4p29.2936
4s28.2036
5p41.104
5s39.189
6s47.688