Thulium (Tm)

Thulium is the 69th element in the periodic table and has a symbol of Tm and atomic number of 69. It has an atomic weight of 168.93422 and a mass number of 169. Thulium has sixty-nine protons and one hundred neutrons in its nucleus, and sixty-nine electrons in six shells. It is located in group Lanthanides, period six and block f of the periodic table. Soft grey metallic element that belongs to the lanthanoids. One natural isotope exists, Tm-169, and seventeen artificial isotopes have been produced. No known uses for the element. Discovered in 1879 by Per Theodor Cleve.

Atomic Number	69
Atomic Weight	168.93422
Mass Number	169

Group
Period	6
Block	f

Protons	69 p⁺
Neutrons	100 n⁰
Electrons	69 e^-

Properties

Physical Properties
Atomic Radius	175 pm 271 pm
Molar Volume	18.1 cm³/mol
Covalent Radius	164 pm 131 pm 190 pm
Metallic Radius
Ionic Radius	103 pm 109 pm 88 pm 99.4 pm 105.2 pm
Crystal Radius	117 pm 123 pm 102 pm 113.4 pm 119.2 pm
Van der Waals Radius	227 pm 267 pm 337.4 pm
Density	9.321 g/cm³ 8,560 kg/m³
Energy
Proton Affinity
Electron Affinity	1.029 eV/particle
Ionization Energy	6.18431 eV/particle 12.05 eV/particle 23.7 eV/particle 42.7 eV/particle 65.43 eV/particle 98 eV/particle 116 eV/particle 133 eV/particle 160 eV/particle 180 eV/particle 205 eV/particle 239 eV/particle 274 eV/particle 295 eV/particle 317 eV/particle 352 eV/particle 387 eV/particle 424 eV/particle 460 eV/particle 500 eV/particle 530 eV/particle 570 eV/particle 603 eV/particle 825 eV/particle 866 eV/particle 911 eV/particle 958 eV/particle 1,004 eV/particle 1,050 eV/particle 1,110 eV/particle 1,157 eV/particle 1,207 eV/particle 1,255 eV/particle 1,442 eV/particle 1,490 eV/particle 1,542 eV/particle 1,591 eV/particle 1,706 eV/particle 1,761 eV/particle 1,889 eV/particle 1,945.2 eV/particle 3,300 eV/particle 3,409 eV/particle 3,528 eV/particle 3,653 eV/particle 3,775 eV/particle 3,895 eV/particle 4,075 eV/particle 4,199 eV/particle 4,335 eV/particle 4,461 eV/particle 4,812 eV/particle 4,922 eV/particle 5,044 eV/particle 5,157 eV/particle 5,527 eV/particle 5,656 eV/particle 5,901 eV/particle 6,023 eV/particle 13,347 eV/particle 13,651 eV/particle 13,988 eV/particle 14,300 eV/particle 15,663 eV/particle 16,036 eV/particle 16,500 eV/particle 16,814.34 eV/particle 67,965.26 eV/particle 69,387.34 eV/particle

Heat of Vaporization	232 kJ/mol
Heat of Fusion
Heat of Formation	232.2 kJ/mol
Electrons
Electron Shells	2, 8, 18, 31, 8, 2

Valence Electrons	2 ⓘ

Electron Configuration	[Xe] 4f¹³ 6s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹³ 6s²

Oxidation States	0, 1, 2, 3
Electronegativity	0.2167244 1.25
Electrophilicity Index	1.2616079623752015 eV/particle
States of Matter
Phase	Solid
Gas Phase
Boiling Point	2,223.15 K
Melting Point	1,818.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Thulium is a Silver. Tm has a CPK of #ff1493, Jmol of #00d452, and MOLCAS GV of #00d452. The Appearance of Element 69 is silvery gray.
Color	Silver #ff1493 #00d452 #00d452
Appearance	silvery gray
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion	0.0000133 1/K
Molar Heat Capacity	27.03 J/(mol K)
Specific Heat Capacity	0.16 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type	Conductor
Electrical Conductivity	1.4 MS/m
Electrical Resistivity	0.0000007 m Ω
Superconducting Point
Magnetism
Type	paramagnetic
Magnetic Susceptibility (Mass)	0.00000199 m³/Kg
Magnetic Susceptibility (Molar)	0.000000336179 m³/mol
Magnetic Susceptibility (Volume)	0.0185488
Magnetic Ordering
Curie Point	25 K
Neel Point	56 K
Structure
The Crystal Structure of Thulium is HEX. The lattice constant of Tm is 3.54 Å. The lattice angles of Element 69 are π/2, π/2, 2 π/3.
Crystal Structure	Simple Hexagonal (HEX)
Lattice Constant	3.54 Å
Lattice Angles	π/2, π/2, 2 π/3
Mechanical Properties
Thulium has a Brinell of 471 MPa, and Vickers of 520 MPa. The Bulk Modulus of Tm is 45 GPa. The Shear Modulus of Element 69 is 31 GPa. The Young Modulus of Thulium (Tm) is 74 GPa. The Poisson Ratio of Thulium is 0.21.
Hardness	471 MPa 520 MPa
Bulk Modulus	45 GPa
Shear Modulus	31 GPa
Young's Modulus	74 GPa
Poisson Ratio	0.21
Speed of Sound
Classification
The Glawe Number of Thulium is 20. The Mendeleev Number of Tm is 37. The Pettifor Number of Element 69 is 22. The Geochemical Class of Thulium (Tm) is rare earth & related. The Goldschmidt Class of Thulium is litophile.
Category	Lanthanides, Lanthanides
CAS Group
IUPAC Group
Glawe Number	20
Mendeleev Number	37
Pettifor Number	22
Geochemical Class	rare earth & related
Goldschmidt Class	litophile
Other
The Dipole Polarizability of Thulium is 144 plus or minus 15 a₀. Tm has a C6 Dispersion Coefficient (GB) of 2020 a₀. The Allotropes of Element 69 is . The Neutron Cross Section of Thulium (Tm) is 105. The Neutron Mass Absorption of Thulium is 0.025. The Quantum Numbers of Tm is 2F7/2. The Space Group of Element 69 is 194 (P63/mmc).
Gas Basicity
Dipole Polarizability	144 ± 15 a₀
C6 Dispersion Coefficient	2,020 a₀
Allotropes
Neutron Cross Section	105
Neutron Mass Absorption	0.025
Quantum Numbers	2F7/2
Space Group	194 (P63/mmc)

Isotopes of Thulium

Stable Isotopes	1
Unstable Isotopes	38
Radioactive Isotopes	38

¹⁴⁴Tm

Mass Number	144
Neutron Number	75
Relative Atomic Mass	143.976211 ± 0.000429 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	2.3 ± 0.9 us
Spin	10
Quadrupole Moment
Discovery Year	2005
Parity	+

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

¹⁴⁵Tm

Mass Number	145
Neutron Number	76
Relative Atomic Mass	144.970389 ± 0.00021 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	3.17 ± 0.2 us
Spin	11/2
Quadrupole Moment
Discovery Year	1998
Parity	-

Decay Mode	Intensity
p (proton emission)	100%

¹⁴⁶Tm

Mass Number	146
Neutron Number	77
Relative Atomic Mass	145.966661 ± 0.000215 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	155 ± 20 ms
Spin	1
Quadrupole Moment
Discovery Year	1993
Parity	+

Decay Mode	Intensity
p (proton emission)	100%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
β⁺ p (β⁺-delayed proton emission)

¹⁴⁷Tm

Mass Number	147
Neutron Number	78
Relative Atomic Mass	146.961379887 ± 0.000007341 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	580 ± 30 ms
Spin	11/2
Quadrupole Moment
Discovery Year	1982
Parity	-

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	85%
p (proton emission)	15%

¹⁴⁸Tm

Mass Number	148
Neutron Number	79
Relative Atomic Mass	147.958384026 ± 0.000011 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	700 ± 200 ms
Spin	10
Quadrupole Moment
Discovery Year	1982
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)

¹⁴⁹Tm

Mass Number	149
Neutron Number	80
Relative Atomic Mass	148.952828 ± 0.000215 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	900 ± 200 ms
Spin	11/2
Quadrupole Moment
Discovery Year	1987
Parity	-

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	0.26%

¹⁵⁰Tm

Mass Number	150
Neutron Number	81
Relative Atomic Mass	149.95009 ± 0.00021 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	1
Quadrupole Moment
Discovery Year	1982
Parity	+

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

¹⁵¹Tm

Mass Number	151
Neutron Number	82
Relative Atomic Mass	150.945494433 ± 0.000020799 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	4.17 ± 0.11 s
Spin	11/2
Quadrupole Moment
Discovery Year	1982
Parity	-

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

¹⁵²Tm

Mass Number	152
Neutron Number	83
Relative Atomic Mass	151.944476 ± 0.000058 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	8 ± 1 s
Spin	2
Quadrupole Moment
Discovery Year	1980
Parity

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

¹⁵³Tm

Mass Number	153
Neutron Number	84
Relative Atomic Mass	152.942058023 ± 0.00001286 Da
G-Factor	1.26 ± 0.02
Abundance
Radioactivity	☢️ Radioactive
Half Life	1.48 ± 0.01 s
Spin	11/2
Quadrupole Moment	0.5 ± 1
Discovery Year	1964
Parity	-

Decay Mode	Intensity
α (α emission)	91%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	9%

¹⁵⁴Tm

Mass Number	154
Neutron Number	85
Relative Atomic Mass	153.941570062 ± 0.000015471 Da
G-Factor	-0.57 ± 0.01
Abundance
Radioactivity	☢️ Radioactive
Half Life	8.1 ± 0.3 s
Spin	2
Quadrupole Moment	0.4 ± 0.9
Discovery Year	1964
Parity

Decay Mode	Intensity
α (α emission)	54%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	46%

¹⁵⁵Tm

Mass Number	155
Neutron Number	86
Relative Atomic Mass	154.939209576 ± 0.000010651 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	21.6 ± 0.2 s
Spin	11/2
Quadrupole Moment
Discovery Year	1971
Parity	-

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	99.17%
α (α emission)	0.83%

¹⁵⁶Tm

Mass Number	156
Neutron Number	87
Relative Atomic Mass	155.938985746 ± 0.000015328 Da
G-Factor	0.2 ± 0.015
Abundance
Radioactivity	☢️ Radioactive
Half Life	83.8 ± 1.8 s
Spin	2
Quadrupole Moment	-0.48 ± 0.11
Discovery Year	1971
Parity	-

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	0.064%

¹⁵⁷Tm

Mass Number	157
Neutron Number	88
Relative Atomic Mass	156.936973 ± 0.00003 Da
G-Factor	0.952 ± 0.03
Abundance
Radioactivity	☢️ Radioactive
Half Life	3.63 ± 0.09 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1974
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	7.5%

¹⁵⁸Tm

Mass Number	158
Neutron Number	89
Relative Atomic Mass	157.936979525 ± 0.000027074 Da
G-Factor	0.02 ± 0.01
Abundance
Radioactivity	☢️ Radioactive
Half Life	3.98 ± 0.06 m
Spin	2
Quadrupole Moment	0.74 ± 0.11
Discovery Year	1970
Parity	-

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

¹⁵⁹Tm

Mass Number	159
Neutron Number	90
Relative Atomic Mass	158.934975 ± 0.00003 Da
G-Factor	1.368 ± 0.012
Abundance
Radioactivity	☢️ Radioactive
Half Life	9.13 ± 0.16 m
Spin	5/2
Quadrupole Moment	1.93 ± 0.07
Discovery Year	1971
Parity	+

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

¹⁶⁰Tm

Mass Number	160
Neutron Number	91
Relative Atomic Mass	159.935264177 ± 0.000035089 Da
G-Factor	0.16 ± 0.02
Abundance
Radioactivity	☢️ Radioactive
Half Life	9.4 ± 0.3 m
Spin	1
Quadrupole Moment	0.58 ± 0.04
Discovery Year	1970
Parity	-

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

¹⁶¹Tm

Mass Number	161
Neutron Number	92
Relative Atomic Mass	160.933549 ± 0.00003 Da
G-Factor	0.68571428571429 ± 0.0057142857142857
Abundance
Radioactivity	☢️ Radioactive
Half Life	30.2 ± 0.8 m
Spin	7/2
Quadrupole Moment	2.9 ± 0.07
Discovery Year	1959
Parity	+

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

¹⁶²Tm

Mass Number	162
Neutron Number	93
Relative Atomic Mass	161.934001211 ± 0.000027974 Da
G-Factor	0.068 ± 0.008
Abundance
Radioactivity	☢️ Radioactive
Half Life	21.7 ± 0.19 m
Spin	1
Quadrupole Moment	0.69 ± 0.03
Discovery Year	1963
Parity	-

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

¹⁶³Tm

Mass Number	163
Neutron Number	94
Relative Atomic Mass	162.932658282 ± 0.00000592 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	1.81 ± 0.005 h
Spin	1/2
Quadrupole Moment	0
Discovery Year	1959
Parity	+

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

¹⁶⁴Tm

Mass Number	164
Neutron Number	95
Relative Atomic Mass	163.933538019 ± 0.000026845 Da
G-Factor	2.37 ± 0.03
Abundance
Radioactivity	☢️ Radioactive
Half Life	2 ± 0.1 m
Spin	1
Quadrupole Moment	0.71 ± 0.05
Discovery Year	1960
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
ϵ (electron capture)	61%
e⁺ (positron emission)	39%

¹⁶⁵Tm

Mass Number	165
Neutron Number	96
Relative Atomic Mass	164.932441843 ± 0.000001779 Da
G-Factor	-0.278 ± 0.004
Abundance
Radioactivity	☢️ Radioactive
Half Life	30.06 ± 0.03 h
Spin	1/2
Quadrupole Moment	0
Discovery Year	1953
Parity	+

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

¹⁶⁶Tm

Mass Number	166
Neutron Number	97
Relative Atomic Mass	165.933562136 ± 0.000012401 Da
G-Factor	0.0463 ± 0.00035
Abundance
Radioactivity	☢️ Radioactive
Half Life	7.7 ± 0.03 h
Spin	2
Quadrupole Moment	2.14 ± 0.03
Discovery Year	1948
Parity	+

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

¹⁶⁷Tm

Mass Number	167
Neutron Number	98
Relative Atomic Mass	166.932857206 ± 0.00000135 Da
G-Factor	-0.394 ± 0.004
Abundance
Radioactivity	☢️ Radioactive
Half Life	9.25 ± 0.02 d
Spin	1/2
Quadrupole Moment	0
Discovery Year	1948
Parity	+

Decay Mode	Intensity
ϵ (electron capture)	100%

¹⁶⁸Tm

Mass Number	168
Neutron Number	99
Relative Atomic Mass	167.934178457 ± 0.0000018 Da
G-Factor	0.075666666666667 ± 0.0036666666666667
Abundance
Radioactivity	☢️ Radioactive
Half Life	93.1 ± 0.2 d
Spin	3
Quadrupole Moment	3.23 ± 0.07
Discovery Year	1949
Parity	+

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁻ (β⁻ decay)	0.01%

¹⁶⁹Tm

Mass Number	169
Neutron Number	100
Relative Atomic Mass	168.934218956 ± 0.000000792 Da
G-Factor	-0.462 ± 0.003
Abundance	100
Radioactivity	Stable
Half Life	Not Radioactive ☢️
Spin	1/2
Quadrupole Moment	0
Discovery Year	1934
Parity	+

¹⁷⁰Tm

Mass Number	170
Neutron Number	101
Relative Atomic Mass	169.935807093 ± 0.000000785 Da
G-Factor	0.247 ± 0.004
Abundance
Radioactivity	☢️ Radioactive
Half Life	128.6 ± 0.3 d
Spin	1
Quadrupole Moment	0.74 ± 0.02
Discovery Year	1936
Parity	-

Decay Mode	Intensity
β⁻ (β⁻ decay)	99.869%
ϵ (electron capture)	0.131%

¹⁷¹Tm

Mass Number	171
Neutron Number	102
Relative Atomic Mass	170.936435162 ± 0.000001043 Da
G-Factor	-0.46 ± 0.008
Abundance
Radioactivity	☢️ Radioactive
Half Life	1.92 ± 0.01 y
Spin	1/2
Quadrupole Moment	0
Discovery Year	1948
Parity	+

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

¹⁷²Tm

Mass Number	172
Neutron Number	103
Relative Atomic Mass	171.938406959 ± 0.000005884 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	63.6 ± 0.3 h
Spin	2
Quadrupole Moment
Discovery Year	1956
Parity	-

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

¹⁷³Tm

Mass Number	173
Neutron Number	104
Relative Atomic Mass	172.93960663 ± 0.000004723 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	8.24 ± 0.08 h
Spin	1/2
Quadrupole Moment	0
Discovery Year	1961
Parity	+

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

¹⁷⁴Tm

Mass Number	174
Neutron Number	105
Relative Atomic Mass	173.942174061 ± 0.00004801 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	5.4 ± 0.1 m
Spin	4
Quadrupole Moment
Discovery Year	1960
Parity	-

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

¹⁷⁵Tm

Mass Number	175
Neutron Number	106
Relative Atomic Mass	174.94384231 ± 0.000053677 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	15.2 ± 0.5 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1961
Parity

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

¹⁷⁶Tm

Mass Number	176
Neutron Number	107
Relative Atomic Mass	175.946997707 ± 0.000107354 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	1.85 ± 0.03 m
Spin	4
Quadrupole Moment
Discovery Year	1961
Parity	+

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

¹⁷⁷Tm

Mass Number	177
Neutron Number	108
Relative Atomic Mass	176.948932 ± 0.000215 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life	95 ± 7 s
Spin	1/2
Quadrupole Moment	0
Discovery Year	1989
Parity	+

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

¹⁷⁸Tm

Mass Number	178
Neutron Number	109
Relative Atomic Mass	177.952506 ± 0.000322 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	1
Quadrupole Moment
Discovery Year	2008
Parity	-

Decay Mode	Intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

¹⁷⁹Tm

Mass Number	179
Neutron Number	110
Relative Atomic Mass	178.955018 ± 0.000429 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	1/2
Quadrupole Moment	0
Discovery Year	2012
Parity	+

Decay Mode	Intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

¹⁸⁰Tm

Mass Number	180
Neutron Number	111
Relative Atomic Mass	179.959023 ± 0.000429 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin
Quadrupole Moment
Discovery Year	2012
Parity

Decay Mode	Intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

¹⁸¹Tm

Mass Number	181
Neutron Number	112
Relative Atomic Mass	180.961954 ± 0.000537 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin	1/2
Quadrupole Moment	0
Discovery Year	2012
Parity	+

Decay Mode	Intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

¹⁸²Tm

Mass Number	182
Neutron Number	113
Relative Atomic Mass	181.966194 ± 0.000537 Da
G-Factor
Abundance
Radioactivity	☢️ Radioactive
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

Decay Mode	Intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

History

Thulium was discovered by Swedish chemist Per Teodor Cleve in 1879 by looking for impurities in the oxides of other rare earth elements. The first researcher to obtain nearly pure thulium was Charles James, a British expatriate working on a large scale at New Hampshire College in Durham. High-purity thulium oxide was first offered commercially in the late 1950s. Named after Thule, the earliest name for Scandinavia

Discoverers	Per Theodor Cleve
Discovery Location	Sweden
Discovery Year	1879
Etymology (Name Origin)	From Thule ancient name of Scandinavia.
Pronunciation	THOO-li-em (English)

Thulium is considered to be non-toxic

Thulium ore occurs most commonly in China

Uses

Thulium is used to dope yttrium aluminum garnets used in lasers. It has also been used in high-temperature superconductors similarly to yttrium. Thulium has use in ferrites, ceramic magnetic materials that are used in microwave equipment. Thulium is used in euro banknotes for its blue fluorescence under UV light to defeat counterfeiters. Radioactive thulium is used to power portable x-ray machines, eliminating the need for electrical equipment.

Sources

Found with other rare earths in the minerals gadolinite, euxenite, xenotime, and monazite. Monazite is often 50% rare earth by weight and 0.007% thulium.

Abundance
Abundance in Earth's crust	0.52 mg/kg
Natural Abundance (Oceans)	0.00000017 mg/L
Natural Abundance (Human Body)
Natural Abundance (Meteor)	0.0000029 %
Natural Abundance (Sun)	0.00000002 %
Abundance in Universe	0.00000001 %

Nuclear Screening Constants

1	s	1.3437
2	p	4.3588
2	s	18.0522
3	d	13.6257
3	p	20.5239
3	s	21.0816
4	d	36.056
4	f	40.366
4	p	33.012
4	s	31.8624
5	p	51.272
5	s	48.963
6	s	60.4158

Also Known As

Tm
element 69
69Tm

Translations

Frenchthulium
GermanThulium
Amharicቱሊየም
Arabicثوليوم
AzerbaijaniTulium
Belarusianтулій
Bulgarianтулий
Banglaথুলিয়াম
Bosniantulij
Catalantuli
CorsicanTuliu
Czechthulium
ChuvashТули
WelshThwliwm
Danishthulium
Greekθούλιο
Esperantotulio
Spanishtulio
EstonianTuulium
Basquetulio
Persianتولیم
Finnishtulium
FriulianTuli
Irishtúiliam
GalicianTulio
ManxThulium
Hakka Chinesethulium
HawaiianThulium
Hebrewתוליום
Hindiथुलियम
Fiji HindiThulium
CroatianTulij
Hungariantúlium
Armenianթուլիում
Interlinguathulium
Indonesiantulium
Idotulio
Icelandictúlín
Italiantulio
Japaneseツリウム
Lojbanjinmrtuli
Georgianთულიუმი
Kannadaಥುಲಿಯಮ್
Korean툴륨
KomiТулий
Latinthulium
LuxembourgishThulium
LigurianTulio
LithuanianTulis
Latviantūlijs
Malayalamതൂലിയം
Marathiथुलियम
Western MariТулий
MalayTulium
Dutchthulium
Norwegian Nynorskthulium
Polishtul
pnbتھلیم
Portuguesetúlio
QuechuaThulyu
Romaniantuliu
Russianтулий
SakhaТулиум
Siciliantuliu
Serbo-CroatianTulijum
Slovaktúlium
SlovenianTulij
Serbianтулијум
Saterland FrisianThulium
Swedishtulium
Tamilதூலியம்
Thaiทูเลียม
TurkishTulyum
Uyghurتۇلىي
Ukrainianтулій
Urduتھلیئم
VepsTulii
Vietnamesethuli
WarayTulyo
KalmykТулиум
YorubaThulium
Chinese銩
Norwegian Bokmålthulium
CebuanoTulyo
Central Kurdishتوولیۆم
AlbanianTuliumi
Macedonianтулиум
BretonTuliom
KazakhТулий
Odiaଥୁଲିଅମ
Gujaratiથુલિયમ
Occitantuli
TatarТулий
Burmeseကျူလီယမ်
PiedmonteseTulio
Cantonese銩
Belarusian (Taraskievica orthography)Туль
AromanianTuliu
UzbekTuliy
KyrgyzТулий
Newariथुलियम
Sanskritथुलियम
Maltesetulju
Scottish GaelicTuilium
Portuguese (Brazil)túlio
Nepaliथुलियम
Paliथुलियम
Teluguథులియం
cdoThulium
Min Nan ChineseThulium
AsturianTuliu
LimburgishThulium
Bhojpuriथुलियम
Tajikтулий
Lingua Franca Novatulio
TagalogTulyo
Literary Chinese銩
AfrikaansTulium
kbpTʊlɩyɔm
oloTulii
Northern FrisianTuulium
Chinese (Traditional)銩
Chinese (Taiwan)銩
Mongolianтули
Wu Chinese铥
SardinianTùliu
English (United Kingdom)thulium
Moroccan Arabicثوليوم
Egyptian Arabicثوليوم
Pashtoتوليوم
CornishThuliom
BalineseThulium
Chinese (Hong Kong SAR China)銩
Punjabiਥੂਲੀਅਮ

Thulium on ChemicalAid

Australian Educational Vocabulary ID	scot/3586
CAS Registry Number	7440-30-4
ChEBI ID	33380
ChemSpider ID	22400
DSSTOX compound identifier	DTXCID1047657
DSSTox substance ID	DTXSID8064692
Den Store Danske ID	thulium
ECHA Substance Infocard ID	100.028.309
Encyclopædia Britannica Online ID	science/thulium
Encyclopædia Universalis ID	thulium
Freebase ID	/m/025sk7j
GND ID	4185369-6
Gran Enciclopèdia Catalana ID	0148772
Great Russian Encyclopedia Online ID	4219056
InChI	InChI=1S/Tm
InChIKey	FRNOGLGSGLTDKL-UHFFFAOYSA-N
KBpedia ID	Thulium
Library of Congress authority ID	sh85135103
MeSH descriptor ID	D013932
NALT ID	60931
NE.se ID	tulium
Namuwiki ID	툴륨
National Library of Israel J9U ID	987007536581905171
OmegaWiki Defined Meaning	367509
OpenAlex ID	C500400820
PubChem CID	23961
RxNorm ID	1311496
Römpp online ID	RD-20-01654
Store norske leksikon ID	thulium
Treccani ID	tulio
UNII	8RKC5ATI4P
USGS Thesaurus ID	1594
WordNet 3.1 Synset ID	14682725-n

Thulium (Tm)

Properties

Isotopes of Thulium

144Tm

145Tm

146Tm

147Tm

148Tm

149Tm

150Tm

151Tm

152Tm

153Tm

154Tm

155Tm

156Tm

157Tm

158Tm

159Tm

160Tm

161Tm

162Tm

163Tm

164Tm

165Tm

166Tm

167Tm

168Tm

169Tm

170Tm

171Tm

172Tm

173Tm

174Tm

175Tm

176Tm

177Tm

178Tm

179Tm

180Tm

181Tm

182Tm