Praseodymium

Praseodymium (Pr)

Soft silvery metallic element, belongs to the lanthanoids. Only natural isotope is Pr-141 which is not radioactive. Fourteen radioactive isotopes have been artificially produced. Used in rare-earth alloys. Discovered in 1885 by C.A. von Welsbach.
Atomic Number59
Atomic Weight140.90766
Mass Number141
Group
Period6
Blockf
Protons59 p+
Neutrons82 n0
Electrons59 e-
Praseodym 1.jpg Animated Bohr Model of Pr (Praseodymium) Enhanced Bohr Model of Pr (Praseodymium) Bohr Model: Pr (Praseodymium) Orbital Diagram of Pr (Praseodymium)

Properties

Atomic Radius
185 pm
Molar Volume
Covalent Radius
176 pm
Metallic Radius
Ionic Radius
99 pm
Crystal Radius
113 pm
Van der Waals Radius
240 pm
Density
6.773 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
Heat of Vaporization
331 kJ/mol
Heat of Fusion
11.3 kJ/mol
Heat of Formation
356.9 kJ/mol
Electrons
Electron Shells2, 8, 18, 21, 8, 2
Valence Electrons4
Electron Configuration[Xe] 4f3 6s2
Oxidation States0, 1, 2, 3, 4, 5
Electronegativity
1.13
Electrophilicity
1.1474513688760803 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
3,793.15 K
Melting Point
1,204.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearancegrayish white
Refractive Index
Thermodynamic Properties
Thermal Conductivity
12.5 W/(m K)
Thermal Expansion
0.0000067 1/K
Molar Heat Capacity
Specific Heat Capacity
0.193 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
1.4 MS/m
Electrical Resistivity
0.0000007 m Ω
Superconducting Point
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.000000423 m³/Kg
Magnetic Susceptibility (Molar)
0.000000059604 m³/mol
Magnetic Susceptibility (Volume)
0.0028087
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.67 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
29 GPa
Shear Modulus
15 GPa
Young Modulus
37 GPa
Poisson Ratio
0.28
Speed of Sound
2,280 m/s
Classification
CategoryLanthanides, Lanthanides
CAS Group
IUPAC Group
Glawe Number30
Mendeleev Number17
Pettifor Number31
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
216 ± 20 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
11.4
Neutron Mass Absorption
0.0029
Quantum Numbers4I9/2
Space Group194 (P63/mmc)

Isotopes of Praseodymium

Stable Isotopes1
Unstable Isotopes40
Radioactive Isotopes40

121Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
120.955393 ± 0.000537 Da
Mass Number121
G-Factor
Half Life
12 ± 5 ms
Spin3/2
Quadrupole Moment
Discovery Year2005
Parity

121Pr Decay Modes
Decay ModeIntensity
p (proton emission)100%

122Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
121.951927 ± 0.000537 Da
Mass Number122
G-Factor
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

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

123Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
122.946076 ± 0.000429 Da
Mass Number123
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity+

123Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

124Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
123.94294 ± 0.00043 Da
Mass Number124
G-Factor
Half Life
1.2 ± 0.2 s
Spin
Quadrupole Moment
Discovery Year1986
Parity

124Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

125Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
124.937659 ± 0.000322 Da
Mass Number125
G-Factor
Half Life
3.3 ± 0.7 s
Spin3/2
Quadrupole Moment
Discovery Year2002
Parity+

125Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

126Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
125.93524 ± 0.00021 Da
Mass Number126
G-Factor
Half Life
3.12 ± 0.18 s
Spin4
Quadrupole Moment
Discovery Year1983
Parity

126Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

127Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
126.93071 ± 0.00021 Da
Mass Number127
G-Factor
Half Life
4.2 ± 0.3 s
Spin3/2
Quadrupole Moment
Discovery Year1995
Parity+

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

128Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
127.928791 ± 0.000032 Da
Mass Number128
G-Factor
Half Life
2.85 ± 0.09 s
Spin3
Quadrupole Moment
Discovery Year1985
Parity+

128Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

129Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
128.925095 ± 0.000032 Da
Mass Number129
G-Factor
Half Life
30 ± 4 s
Spin3/2
Quadrupole Moment
Discovery Year1977
Parity+

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

130Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
129.92359 ± 0.000069 Da
Mass Number130
G-Factor
Half Life
40 ± 0.4 s
Spin6
Quadrupole Moment
Discovery Year1977
Parity

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

131Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
130.92023496 ± 0.000050451 Da
Mass Number131
G-Factor
Half Life
1.5 ± 0.03 m
Spin3/2
Quadrupole Moment
Discovery Year1977
Parity+

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

132Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
131.91924 ± 0.000031 Da
Mass Number132
G-Factor
Half Life
1.49 ± 0.11 m
Spin2
Quadrupole Moment
Discovery Year1974
Parity+

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

133Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
132.916330558 ± 0.000013416 Da
Mass Number133
G-Factor
Half Life
6.5 ± 0.3 m
Spin5/2
Quadrupole Moment
Discovery Year1970
Parity+

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

134Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
133.915696729 ± 0.00002181 Da
Mass Number134
G-Factor
Half Life
17 ± 2 m
Spin2
Quadrupole Moment
Discovery Year1967
Parity-

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

135Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
134.913111772 ± 0.000012686 Da
Mass Number135
G-Factor
Half Life
24 ± 1 m
Spin3/2
Quadrupole Moment
Discovery Year1954
Parity+

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

136Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
135.91267747 ± 0.000012296 Da
Mass Number136
G-Factor
Half Life
13.1 ± 0.1 m
Spin2
Quadrupole Moment
Discovery Year1968
Parity+

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

137Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
136.910679183 ± 0.000008733 Da
Mass Number137
G-Factor
Half Life
1.28 ± 0.03 h
Spin5/2
Quadrupole Moment
Discovery Year1958
Parity+

137Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

138Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
137.910757495 ± 0.000010748 Da
Mass Number138
G-Factor
Half Life
1.45 ± 0.05 m
Spin1
Quadrupole Moment
Discovery Year1951
Parity+

138Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

139Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
138.9089327 ± 0.000003917 Da
Mass Number139
G-Factor
Half Life
4.41 ± 0.04 h
Spin5/2
Quadrupole Moment
Discovery Year1951
Parity+

139Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

140Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
139.9090856 ± 0.000006593 Da
Mass Number140
G-Factor
Half Life
3.39 ± 0.01 m
Spin1
Quadrupole Moment
Discovery Year1938
Parity+

140Pr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
e+ (positron emission)48.7%
ϵ (electron capture)51.3%

141Pr

Abundance
100
Relative Atomic Mass
140.907659604 ± 0.000001607 Da
Mass Number141
G-Factor
1.7064 ± 0.0012
Half Life
Spin5/2
Quadrupole Moment
-0.077 ± 0.006
Discovery Year1924
Parity+

142Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
141.91005164 ± 0.000001607 Da
Mass Number142
G-Factor
0.117 ± 0.0005
Half Life
19.12 ± 0.04 h
Spin2
Quadrupole Moment
0.039 ± 0.017
Discovery Year1935
Parity-

142Pr Decay Modes
Decay ModeIntensity
β (β decay)100%
ϵ (electron capture)0.0164%

143Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
142.910822624 ± 0.000001949 Da
Mass Number143
G-Factor
0.77 ± 0.0014285714285714
Half Life
13.57 ± 0.02 d
Spin7/2
Quadrupole Moment
0.77 ± 0.16
Discovery Year1948
Parity+

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

144Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
143.913310682 ± 0.000002907 Da
Mass Number144
G-Factor
0
Half Life
17.28 ± 0.05 m
Spin0
Quadrupole Moment
0
Discovery Year1951
Parity-

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

145Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
144.914517987 ± 0.000007674 Da
Mass Number145
G-Factor
Half Life
5.984 ± 0.01 h
Spin7/2
Quadrupole Moment
Discovery Year1954
Parity+

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

146Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
145.91768763 ± 0.000036882 Da
Mass Number146
G-Factor
Half Life
24.09 ± 0.1 m
Spin2
Quadrupole Moment
Discovery Year1953
Parity-

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

147Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
146.919007438 ± 0.00001702 Da
Mass Number147
G-Factor
Half Life
13.39 ± 0.04 m
Spin3/2
Quadrupole Moment
Discovery Year1964
Parity+

147Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

148Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
147.922129992 ± 0.000016147 Da
Mass Number148
G-Factor
Half Life
2.29 ± 0.02 m
Spin1
Quadrupole Moment
Discovery Year1964
Parity-

148Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

149Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
148.9237361 ± 0.0000106 Da
Mass Number149
G-Factor
Half Life
2.26 ± 0.07 m
Spin5/2
Quadrupole Moment
Discovery Year1964
Parity+

149Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

150Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
149.926676391 ± 0.000009677 Da
Mass Number150
G-Factor
Half Life
6.19 ± 0.16 s
Spin1
Quadrupole Moment
Discovery Year1970
Parity-

150Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

151Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
150.928309066 ± 0.000012506 Da
Mass Number151
G-Factor
Half Life
18.9 ± 0.07 s
Spin3/2
Quadrupole Moment
Discovery Year1990
Parity-

151Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

152Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
151.9315529 ± 0.0000199 Da
Mass Number152
G-Factor
Half Life
3.57 ± 0.11 s
Spin4
Quadrupole Moment
Discovery Year1983
Parity+

152Pr Decay Modes
Decay ModeIntensity
β (β decay)100%

153Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
152.933903511 ± 0.000012755 Da
Mass Number153
G-Factor
Half Life
4.28 ± 0.11 s
Spin3/2
Quadrupole Moment
Discovery Year1987
Parity-

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

154Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
153.937885165 ± 0.00010736 Da
Mass Number154
G-Factor
Half Life
2.3 ± 0.09 s
Spin3
Quadrupole Moment
Discovery Year1988
Parity+

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

155Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
154.940509193 ± 0.000018462 Da
Mass Number155
G-Factor
Half Life
1.47 ± 0.3 s
Spin3/2
Quadrupole Moment
Discovery Year1992
Parity-

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

156Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
155.9447669 ± 0.0000011 Da
Mass Number156
G-Factor
Half Life
444 ± 6 ms
Spin1
Quadrupole Moment
Discovery Year1992
Parity+

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

157Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
156.9480031 ± 0.0000034 Da
Mass Number157
G-Factor
Half Life
307 ± 21 ms
Spin3/2
Quadrupole Moment
Discovery Year2017
Parity-

157Pr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

158Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
157.952603 ± 0.000322 Da
Mass Number158
G-Factor
Half Life
181 ± 14 ms
Spin5
Quadrupole Moment
Discovery Year2016
Parity-

158Pr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

159Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
158.956232 ± 0.000429 Da
Mass Number159
G-Factor
Half Life
134 ± 43 ms
Spin3/2
Quadrupole Moment
Discovery Year2017
Parity-

159Pr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

160Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
159.961138 ± 0.000429 Da
Mass Number160
G-Factor
Half Life
170 ± 140 ms
Spin1
Quadrupole Moment
Discovery Year2017
Parity+

160Pr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

161Pr

AbundanceRadioactive ☢️
Relative Atomic Mass
160.965121 ± 0.000537 Da
Mass Number161
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year2018
Parity-

161Pr Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

History

Praseodymium was first identified in 1885, in Vienna, by the Austrian chemist Carl Auer von Welsbach. It was discovered in didymium, a substance incorrectly said by Carl Gustav Mosander to be a new element in 1841. Pure metallic praseodymium was first produced in 1931. From the Greek word prasios, green, and didymos, twin

DiscoverersC.F. Aver von Welsbach
Discovery LocationAustria
Discovery Year1885
Etymology (Name Origin)Greek: prasios and didymos (green twin); from its green salts.
Pronunciationpra-si-eh-DIM-i-em (English)
Praseodymium is considered to be moderately toxic
Praseodymium is usually stored under a light mineral oil or sealed in glass

Uses

Praseodymium is used as an alloying agent with magnesium to create high-strength metals that are used in aircraft engines. Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal. Praseodymium is used to make specialized yellow glass goggles for glass blowers and welders. Used with neodymium to make lenses for glass maker's goggles since it filters out the yellow light present in glass blowing. Alloyed with magnesium creates a high-strength metal used in aircraft engines. Makes up 5% of Mich metal.

Sources

Obtained from same salts as neodymium.

Abundance
Abundance in Earth's crust
9.2 mg/kg
Abundance in Oceans
0.00000064 mg/L
Abundance in Human Body
Abundance in Meteor
0.0000098 %
Abundance in Sun
0.0000001 %
Abundance in Universe
0.0000002 %

Nuclear Screening Constants

1s1.1694
2p4.2306
2s15.538
3d13.8476
3p19.1756
3s19.499
4d32.7028
4f37.8992
4p29.9432
4s28.6668
5p43.7165
5s41.387
6s51.2534