Holmium

Holmium (Ho)

Relatively soft and malleable silvery-white metallic element, which is stable in dry air at room temperature. It oxidizes in moist air and at high temperatures. It belongs to the lanthanoids. A rare-earth metal, it is found in the minerals monazite and gadolinite. It possesses unusual magnetic properties. One natural isotope, Ho-165 exists, six radioisotopes exist, the most stable being Ho-163 with a half-life of 4570 years. Holmium is used in some metal alloys, it is also said to stimulate the metabolism. Discovered by Per Theodor Cleve and J.L. Soret in Switzerland in 1879. The name homium comes from the Greek word Holmia which means Sweden. While all holmium compounds should be considered highly toxic, initial evidence seems to indicate that they do not pose much danger. The metal's dust however, is a fire hazard.
Atomic Number67
Atomic Weight164.93033
Mass Number165
Group
Period6
Blockf
Protons67 p+
Neutrons98 n0
Electrons67 e-
Holmium.jpg Animated Bohr Model of Ho (Holmium) Enhanced Bohr Model of Ho (Holmium) Bohr Model: Ho (Holmium) Orbital Diagram of Ho (Holmium)

Properties

Atomic Radius
175 pm
Molar Volume
Covalent Radius
166 pm
Metallic Radius
Ionic Radius
90.1 pm
Crystal Radius
104.1 pm
Van der Waals Radius
230 pm
Density
8.8 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
Heat of Vaporization
301 kJ/mol
Heat of Fusion
Heat of Formation
300.6 kJ/mol
Electrons
Electron Shells2, 8, 18, 29, 8, 2
Valence Electrons3
Electron Configuration[Xe] 4f11 6s2
Oxidation States0, 2, 3
Electronegativity
1.23
Electrophilicity
Phases
PhaseSolid
Gas Phase
Boiling Point
2,973.15 K
Melting Point
1,745.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearancesilvery white
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
0.0000112 1/K
Molar Heat Capacity
27.15 J/(mol K)
Specific Heat Capacity
0.165 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
1.1 MS/m
Electrical Resistivity
0.00000094 m Ω
Superconducting Point
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.00000549 m³/Kg
Magnetic Susceptibility (Molar)
0.000000905467 m³/mol
Magnetic Susceptibility (Volume)
0.0482845
Magnetic Ordering
Curie Point
20 K
Neel Point
132 K
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.58 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
40 GPa
Shear Modulus
26 GPa
Young Modulus
65 GPa
Poisson Ratio
0.23
Speed of Sound
2,760 m/s
Classification
CategoryLanthanides, Lanthanides
CAS Group
IUPAC Group
Glawe Number23
Mendeleev Number33
Pettifor Number24
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
156 ± 10 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
64
Neutron Mass Absorption
0.015
Quantum Numbers4I15/2
Space Group194 (P63/mmc)

Isotopes of Holmium

Stable Isotopes1
Unstable Isotopes38
Radioactive Isotopes38

140Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
139.968526 ± 0.000537 Da
Mass Number140
G-Factor
Half Life
6 ± 3 ms
Spin8
Quadrupole Moment
Discovery Year1999
Parity+

140Ho Decay Modes
Decay ModeIntensity
p (proton emission)%
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

141Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
140.963108 ± 0.00043 Da
Mass Number141
G-Factor
Half Life
4.1 ± 0.1 ms
Spin7/2
Quadrupole Moment
Discovery Year1998
Parity-

141Ho Decay Modes
Decay ModeIntensity
p (proton emission)100%
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

142Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
141.96001 ± 0.00043 Da
Mass Number142
G-Factor
Half Life
400 ± 100 ms
Spin7
Quadrupole Moment
Discovery Year2001
Parity-

142Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%
p (proton emission)0%

143Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
142.95486 ± 0.00032 Da
Mass Number143
G-Factor
Half Life
Spin11/2
Quadrupole Moment
Discovery Year2000
Parity-

143Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

144Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
143.952109712 ± 0.0000091 Da
Mass Number144
G-Factor
Half Life
700 ± 100 ms
Spin5
Quadrupole Moment
Discovery Year1986
Parity-

144Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

145Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
144.947267392 ± 0.000008 Da
Mass Number145
G-Factor
Half Life
2.4 ± 0.1 s
Spin11/2
Quadrupole Moment
Discovery Year1987
Parity-

145Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

146Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
145.944993503 ± 0.000007071 Da
Mass Number146
G-Factor
Half Life
3.32 ± 0.22 s
Spin6
Quadrupole Moment
Discovery Year1982
Parity-

146Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

147Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
146.940142293 ± 0.000005368 Da
Mass Number147
G-Factor
Half Life
5.8 ± 0.4 s
Spin11/2
Quadrupole Moment
Discovery Year1982
Parity-

147Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

148Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
147.937743925 ± 0.00009 Da
Mass Number148
G-Factor
Half Life
2.2 ± 1.1 s
Spin1
Quadrupole Moment
Discovery Year1979
Parity+

148Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

149Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
148.933820457 ± 0.000012866 Da
Mass Number149
G-Factor
Half Life
21.1 ± 0.2 s
Spin11/2
Quadrupole Moment
Discovery Year1979
Parity-

149Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

150Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
149.933498353 ± 0.000015209 Da
Mass Number150
G-Factor
Half Life
76.8 ± 1.8 s
Spin2
Quadrupole Moment
Discovery Year1963
Parity

150Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

151Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
150.931698176 ± 0.000008908 Da
Mass Number151
G-Factor
Half Life
35.2 ± 0.1 s
Spin11/2
Quadrupole Moment
Discovery Year1963
Parity-

151Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)88%
α (α emission)22%

152Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
151.931717618 ± 0.000013449 Da
Mass Number152
G-Factor
-0.51 ± 0.01
Half Life
161.8 ± 0.3 s
Spin2
Quadrupole Moment
0.1 ± 0.2
Discovery Year1963
Parity-

152Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)88%
α (α emission)12%

153Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
152.930206671 ± 0.000005438 Da
Mass Number153
G-Factor
1.2345454545455 ± 0.0090909090909091
Half Life
2.01 ± 0.03 m
Spin11/2
Quadrupole Moment
-1.1 ± 0.5
Discovery Year1963
Parity-

153Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.949%
α (α emission)0.051%

154Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
153.930606776 ± 0.00000882 Da
Mass Number154
G-Factor
-0.3205 ± 0.003
Half Life
11.76 ± 0.19 m
Spin2
Quadrupole Moment
0.19 ± 0.1
Discovery Year1966
Parity-

154Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.981%
α (α emission)0.019%

155Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
154.929103363 ± 0.000018754 Da
Mass Number155
G-Factor
1.4 ± 0.012
Half Life
48 ± 2 m
Spin5/2
Quadrupole Moment
1.56 ± 0.12
Discovery Year1959
Parity+

155Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

156Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
155.929641634 ± 0.000041249 Da
Mass Number156
G-Factor
0.745 ± 0.0075
Half Life
56 ± 1 m
Spin4
Quadrupole Moment
2.4 ± 0.18
Discovery Year1957
Parity-

156Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

157Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
156.928251974 ± 0.000025194 Da
Mass Number157
G-Factor
1.24 ± 0.0085714285714286
Half Life
12.6 ± 0.2 m
Spin7/2
Quadrupole Moment
3.05 ± 0.13
Discovery Year1966
Parity-

157Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

158Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
157.92894491 ± 0.000029099 Da
Mass Number158
G-Factor
0.7552 ± 0.0006
Half Life
11.3 ± 0.4 m
Spin5
Quadrupole Moment
4.2 ± 0.4
Discovery Year1961
Parity+

158Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

159Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
158.927718683 ± 0.000003268 Da
Mass Number159
G-Factor
1.22 ± 0.0085714285714286
Half Life
33.05 ± 0.11 m
Spin7/2
Quadrupole Moment
3.27 ± 0.13
Discovery Year1958
Parity-

159Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

160Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
159.928735538 ± 0.00001612 Da
Mass Number160
G-Factor
0.74 ± 0.006
Half Life
25.6 ± 0.3 m
Spin5
Quadrupole Moment
4 ± 0.2
Discovery Year1950
Parity+

160Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

161Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
160.927861815 ± 0.000002309 Da
Mass Number161
G-Factor
1.2114285714286 ± 0.0085714285714286
Half Life
2.48 ± 0.05 h
Spin7/2
Quadrupole Moment
3.3 ± 0.11
Discovery Year1954
Parity-

161Ho Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

162Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
161.929102543 ± 0.00000333 Da
Mass Number162
G-Factor
2.32 ± 0.03
Half Life
15 ± 1 m
Spin1
Quadrupole Moment
Discovery Year1957
Parity+

162Ho Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

163Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
162.92874026 ± 0.000000744 Da
Mass Number163
G-Factor
1.2057142857143 ± 0.011428571428571
Half Life
4.57 ± 0.025 ky
Spin7/2
Quadrupole Moment
3.7 ± 0.6
Discovery Year1957
Parity-

163Ho Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

164Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
163.930240548 ± 0.000001492 Da
Mass Number164
G-Factor
Half Life
28.8 ± 0.5 m
Spin1
Quadrupole Moment
Discovery Year1938
Parity+

164Ho Decay Modes
Decay ModeIntensity
ϵ (electron capture)61%
β+ (β+ decay; β+ = ϵ + e+)39%

165Ho

Abundance
100
Relative Atomic Mass
164.930329116 ± 0.000000844 Da
Mass Number165
G-Factor
1.1885714285714 ± 0.0085714285714286
Half Life
Spin7/2
Quadrupole Moment
3.58 ± 0.02
Discovery Year1934
Parity-

166Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
165.932291209 ± 0.000000844 Da
Mass Number166
G-Factor
0
Half Life
26.812 ± 0.007 h
Spin0
Quadrupole Moment
0
Discovery Year1936
Parity-

166Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

167Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
166.933140254 ± 0.00000557 Da
Mass Number167
G-Factor
Half Life
3.1 ± 0.1 h
Spin7/2
Quadrupole Moment
Discovery Year1955
Parity-

167Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

168Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
167.935523766 ± 0.000032207 Da
Mass Number168
G-Factor
Half Life
2.99 ± 0.07 m
Spin3
Quadrupole Moment
Discovery Year1960
Parity+

168Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

169Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
168.93687989 ± 0.000021522 Da
Mass Number169
G-Factor
Half Life
4.72 ± 0.1 m
Spin7/2
Quadrupole Moment
Discovery Year1963
Parity-

169Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

170Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
169.939626548 ± 0.000053697 Da
Mass Number170
G-Factor
Half Life
2.76 ± 0.05 m
Spin6
Quadrupole Moment
Discovery Year1960
Parity+

170Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

171Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
170.941472713 ± 0.000644128 Da
Mass Number171
G-Factor
Half Life
53 ± 2 s
Spin7/2
Quadrupole Moment
Discovery Year1989
Parity-

171Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

172Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
171.94473 ± 0.00021 Da
Mass Number172
G-Factor
0
Half Life
25 ± 3 s
Spin0
Quadrupole Moment
0
Discovery Year1991
Parity+

172Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

173Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
172.94702 ± 0.00032 Da
Mass Number173
G-Factor
Half Life
7.1 ± 0.4 s
Spin7/2
Quadrupole Moment
Discovery Year2012
Parity-

173Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

174Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
173.950757 ± 0.000322 Da
Mass Number174
G-Factor
Half Life
3.7 ± 0.4 s
Spin8
Quadrupole Moment
Discovery Year2012
Parity-

174Ho Decay Modes
Decay ModeIntensity
β (β decay)100%

175Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
174.953516 ± 0.000429 Da
Mass Number175
G-Factor
Half Life
1.88 ± 0.55 s
Spin7/2
Quadrupole Moment
Discovery Year2012
Parity-

175Ho Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

176Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
175.957713 ± 0.000537 Da
Mass Number176
G-Factor
Half Life
Spin4
Quadrupole Moment
Discovery Year2012
Parity+

176Ho Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

177Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
176.961052 ± 0.000537 Da
Mass Number177
G-Factor
Half Life
Spin7/2
Quadrupole Moment
Discovery Year2018
Parity-

177Ho Decay Modes
Decay ModeIntensity
β (β decay)100%
n (neutron emission)%

178Ho

AbundanceRadioactive ☢️
Relative Atomic Mass
177.965507 ± 0.000537 Da
Mass Number178
G-Factor
Half Life
Spin2
Quadrupole Moment
Discovery Year2018
Parity+

178Ho Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

History

Holmium was discovered by Swiss chemists Marc Delafontaine and Jacques-Louis Soret in 1878. They noticed the aberrant spectrographic absorption bands of the then-unknown element. Later in 1878, Per Teodor Cleve independently discovered the element while he was working on erbia earth. From the Latin word Holmia meaning Stockholm

DiscoverersJ.L. Soret
Discovery LocationSwitzerland
Discovery Year1878
Etymology (Name Origin)From Holmia, the Latinized name for Stockholm, Sweden.
PronunciationHOLE-mi-em (English)
Holmium is considered to be of low toxicity
Holmium has the highest magnetic strength of any naturally occurring element

Uses

Holmium is used to create the strongest artificially generated magnetic fields, when placed within high-strength magnets as a magnetic pole piece. It is one of the colorants used for cubic zirconia and glass, providing yellow or red coloring. Holmium isotopes are good neutron absorbers and are used in nuclear reactor control rods. It has very few practical applications; however, it has some unusual magnetic properties that offer some hope for future applications.

Sources

Occurs in gadolinite. Most often from monazite which is often 50% rare earth and typically 0.05% holmium.

Abundance
Abundance in Earth's crust
1.3 mg/kg
Abundance in Oceans
0.00000022 mg/L
Abundance in Human Body
Abundance in Meteor
0.0000059 %
Abundance in Sun
0 %
Abundance in Universe
0.00000005 %

Nuclear Screening Constants

1s1.3088
2p4.3332
2s17.5444
3d13.6531
3p20.2546
3s20.7649
4d35.3284
4f39.5304
4p32.4372
4s31.688
5p49.661
5s47.424
6s58.561