| Atomic Mass | 168.93422 |
|---|---|
| Electron Configuration | [Xe]6s24f13 |
| Oxidation States | +3 |
| Year Discovered | 1879 |
| Atomic Mass | 168.93422 |
|---|---|
| Electron Configuration | [Xe]6s24f13 |
| Oxidation States | +3 |
| Year Discovered | 1879 |
| Element Name | Thulium |
|---|---|
| Element Symbol | Tm |
| InChI | InChI=1S/Tm |
| InChIKey | FRNOGLGSGLTDKL-UHFFFAOYSA-N |
| Atomic Weight |
168.934 219(5) 168.93422 168.9 168.93422(2) |
|---|---|
| Electron Configuration |
[Xe]6s24f13 |
| Atomic Radius |
Van der Waals Atomic Radius : 227 pm (Van der Waals) Empirical Atomic Radius : 175pm (Empirical) Covalent Atomic Radius : 190(10) pm (Covalent) |
| Oxidation States |
+3 2, 3 (a basic oxide) |
| Ground Level |
2F°7/2 |
| Ionization Energy |
6.184 eV 6.184402 ± 0.000009 eV |
| Electronegativity |
Pauling Scale Electronegativity : 1.25(Pauling Scale) |
| Atomic Spectra |
Lines Holdings Levels Holdings |
| Physical Description |
Solid |
| Element Classification |
Metal |
| Element Period Number |
6 |
| Element Group Number |
- Lanthanide |
| Density |
9.32 grams per cubic centimeter |
| Melting Point |
1818 K (1545°C or 2813°F) 1545°C |
| Boiling Point |
2223 K (1950°C or 3542°F) 1950°C |
| Estimated Crustal Abundance |
5.2×10-1 milligrams per kilogram |
| Estimated Oceanic Abundance |
1.7×10-7 milligrams per liter |
The name derives from Thule, the earliest name for the northernmost part of the civilized world—Scandinavia. It was discovered in 1879 by the Swedish chemist Per Theodor Cleve in a sample of erbium mineral. Thulium was first isolated by the American chemist Charles James in 1911.
Thulium was discovered by Per Theodor Cleve, a Swedish chemist, in 1879. Cleve used the same method Carl Gustaf Mosander used to discover lanthanum, erbium and terbium, he looked for impurities in the oxides of other rare earth elements. He started with erbia, the oxide of erbium (Er2O3), and removed all of the known contaminants. After further processing, he obtained two new materials, one brown and the other green. Cleve named the brown material holmia and the green material thulia. Holmia is the oxide of the element holmium and thulia is the oxide of the element thulium. Today, thulium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that can contain as much as 0.007% thulium.
Named after Thule, the earliest name for Scandinavia. Discovered in 1879 by Cleve. Thulium occurs in small quantities along with other rare earths in a number of minerals. It is obtained commercially from monazite, which contains about 0.007% of the element. Thulium is the least abundant of the rare earth elements, but with new sources recently discovered, it is now considered to be about as rare as silver,gold, or cadmium.
| Year | Atomic Weight (uncertainty) [u] | Reference |
|---|---|---|
| 2021 | 168.934 219(5) | https://doi.org/10.1515/pac-2019-0603 |
| 2017 | 168.934 218(6) | https://doi.org/10.1515/pac-2019-0603 |
| 2013 | 168.934 22(2) | https://doi.org/10.1515/pac-2015-0305 |
| 1995 | 168.934 21(2) | https://doi.org/10.1351/pac199668122339 |
| 1985 | 168.934 21(3) | https://doi.org/10.1351/pac198658121677 |
| 1969 | 168.9342(1) | https://doi.org/10.1351/pac197021010091 |
| 1961 | 168.934 | https://doi.org/10.1021/ja00881a001 |
| 1953 | 168.94 | https://doi.org/10.1039/JR9540004713 |
| 1925 | 169.4 | https://doi.org/10.1039/CT9252700913 |
| 1922 | 169.9 | https://doi.org/10.1021/ja01441a001 |
| 1909 | 168.5 | https://doi.org/10.1021/ja01931a001 |
| 1902 | 171 | https://doi.org/10.1007/BF01370337 |
| Year | Isotope | Abundance (uncertainty) | Reference |
|---|
| 1975, 169Tm, 1, doi:10.1351/pac197647010075 |
Thulium can be isolated by reduction of the oxide with lanthanum metal or by calcium reduction of a closed container. The element is silver-gray, soft, malleable, and ductile, and can be cut with a knife. Twenty five isotopes are known, with atomic masses ranging from 152 to 176. Natural thulium, which is 100% 169Tm, is stable.
Thulium is the least abundant of the naturally occurring rare earth elements. Metallic thulium is relatively expensive and has only recently become available. It currently has no commercial applications, although one of its isotopes, thulium-169, could be used as a radiation source for portable X-ray machines.
Thulium forms no commercially important compounds. Some of thulium's compounds include: thulium oxide (Tm2O3), thulium fluoride (TmF3) and thulium iodide (TmI3).
Because of the relatively high price of the metal, thulium has not yet found many practical applications. 169Tm bombarded in a nuclear reactor can be used as a radiation source in portable X-ray equipment. 171Tm is potentially useful as an energy source. Natural thulium also has possible use in ferrites (ceramic magnetic materials) used in microwave equipment, and can be used for doping fiber lasers. As with other lanthanides, thulium has a low-to-moderate acute toxic rating. It should be handled with care.
See more information at the Thulium compound page.
| CID | Name | Formula | SMILES | Molecular Weight |
|---|---|---|---|---|
| 23961 | thulium | Tm | [Tm] | 168.93422 |
| 161009 | thulium-170 | Tm | [170Tm] | 169.935807 |
| 177428 | thulium-167 | Tm | [167Tm] | 166.93286 |
| 177618 | thulium-166 | Tm | [166Tm] | 165.9336 |
| 178162 | thulium-173 | Tm | [173Tm] | 172.93961 |
| 167068 | thulium-171 | Tm | [171Tm] | 170.93644 |
| 177646 | thulium-172 | Tm | [172Tm] | 171.93841 |
| 185494 | thulium(3+) | Tm+3 | [Tm+3] | 168.93422 |
| 177695 | thulium-162 | Tm | [162Tm] | 161.9340 |
| 178163 | thulium-175 | Tm | [175Tm] | 174.9438 |
| 10329641 | thulium-165 | Tm | [165Tm] | 164.93244 |
| 11378720 | thulium-168 | Tm | [168Tm] | 167.93418 |
| 46898740 | thulium-170(3+) | Tm+3 | [170Tm+3] | 169.935807 |
| Stable Isotope Count | 1 |
|---|
170Tm (with a half-life of about 130 days) is used in the petrochemical industry for industrial radiography to test welds in pipes and tanks [486].
167Tm (with a half-life of 9.2 days) is useful for tumor and bone studies [487]. Stable 169Tm can be bombarded in a nuclear reactor to create 170Tm, via the 169Tm (n, γ) 170Tm reaction, which emits X-rays and has been used in portable X-ray equipment as a radiation source [488]. 170Tm has been used in high-dose-rate (HDR) brachytherapy [489] and for use in radiosynovectomy of medium sized joints (Fig. IUPAC.69.1) [490].
![Fig. IUPAC.69.1: Wholebody single-photon emission computed spectroscopy (colored layer in image) and CT scan of Beagle dog recorded after 4 h of administration of ¹⁷⁰Tm-labeled microparticles [490]. Radioactive-colloid accumulation is displayed in the right knee joint. The Beagle did not suffer any health impairment. Image kindly provided by Dr. Andras Polyak (Dept. of Nuclear Medicine, Hannover Medical School, Germany).](https://pubchem.ncbi.nlm.nih.gov/images/iupac/j_pac-2015-0703_fig_096.jpg)
| Isotope | Atomic Mass (uncertainty) [u] | Abundance (uncertainty) |
|---|---|---|
| 169Tm | 168.934 219(5) | 1 |
| Isotope | Atomic Mass (uncertainty) [u] | Abundance (uncertainty) |
|---|---|---|
| 169Tm | 168.9342179(22) | 1 |
| Nuclide | Atomic Mass and Uncertainty [u] | Half Life and Uncertainty | Discovery Year | Decay Modes, Intensities and Uncertainties [%] |
|---|---|---|---|---|
| 144Tm | 143.976211 ± 0.000429 [Estimated] | 2.3 us ± 0.9 | 2005 | p=?; β+ ? |
| 145Tm | 144.970389 ± 0.00021 [Estimated] | 3.17 us ± 0.20 | 1998 | p=100% |
| 146Tm | 145.966661 ± 0.000215 [Estimated] | 155 ms ± 20 | 1993 | p≈100%; β+ ?; β+p ? |
| 146Tmm | 145.966661 ± 0.000215 [Estimated] | 73 ms ± 7 | 1993 | p=100%; β+ ?; β+p ? |
| 146Tmn | 145.966661 ± 0.000215 [Estimated] | 200 ms ± 3 | 1993 | p=?; β+ ?; β+p ? |
| 147Tm | 146.961379887 ± 0.000007341 | 580 ms ± 30 | 1982 | β+=85±0.5%; p=15±0.5% |
| 147Tmm | 146.961379887 ± 0.000007341 | 360 us ± 40 | 1984 | p=100% |
| 148Tm | 147.958384026 ± 0.000011 | 700 ms ± 200 | 1982 | β+=100%; β+p ? |
| 149Tm | 148.952828 ± 0.000215 [Estimated] | 900 ms ± 200 | 1987 | β+=100%; β+p=0.26±1.5% |
| 149Tmm | 148.952828 ± 0.000215 [Estimated] | 500 ms [Estimated] | β+ ?; β+p ? | |
| 150Tm | 149.950090 ± 0.00021 [Estimated] | 3 s [Estimated] | 1982 | β+=100% |
| 150Tmm | 149.950090 ± 0.00021 [Estimated] | 2.20 s ± 0.06 | 1981 | β+=100%; β+p=1.1±0.3% |
| 150Tmn | 149.950090 ± 0.00021 [Estimated] | 5.2 ms ± 0.3 | 1984 | IT=100[gs=0,m=100] |
| 151Tm | 150.945494433 ± 0.000020799 | 4.17 s ± 0.11 | 1982 | β+=100% |
| 151Tmm | 150.945494433 ± 0.000020799 | 6.6 s ± 2.0 | 1987 | β+=100% |
| 151Tmn | 150.945494433 ± 0.000020799 | 451 ns ± 34 | 1982 | IT=100% |
| 152Tm | 151.944476000 ± 0.000058 | 8.0 s ± 1.0 | 1980 | β+=100% |
| 152Tmm | 151.944476000 ± 0.000058 | 5.2 s ± 0.6 | 1980 | β+=100% |
| 152Tmn | 151.944476000 ± 0.000058 | 301 ns ± 7 | 1986 | IT=100% |
| 153Tm | 152.942058023 ± 0.00001286 | 1.48 s ± 0.01 | 1964 | α=91±0.3%; β+=9±0.3% |
| 153Tmm | 152.942058023 ± 0.00001286 | 2.5 s ± 0.2 | 1988 | α=92±0.3%; β+=8±0.3% |
| 154Tm | 153.941570062 ± 0.000015471 | 8.1 s ± 0.3 | 1964 | α=54±0.5%; β+=46±0.5% |
| 154Tmm | 153.941570062 ± 0.000015471 | 3.30 s ± 0.07 | 1964 | α=58±0.5%; β+=42±0.5%; IT ? |
| 155Tm | 154.939209576 ± 0.000010651 | 21.6 s ± 0.2 | 1971 | β+=99.17±1.7%; α=0.83±1.7% |
| 155Tmm | 154.939209576 ± 0.000010651 | 45 s ± 4 | 1990 | β+≈100%; α ? |
| 156Tm | 155.938985746 ± 0.000015328 | 83.8 s ± 1.8 | 1971 | β+≈100%; α=0.064±1% |
| 156Tmm | 155.938985746 ± 0.000015328 | ~400 ns | 1985 | IT=100% |
| 157Tm | 156.936973000 ± 0.00003 | 3.63 m ± 0.09 | 1974 | β+=100%; α=7.5e-4±2.5% |
| 157Tmm | 156.936973000 ± 0.00003 | 1.6 s | 2008 | β+ ?; IT ? |
| 158Tm | 157.936979525 ± 0.000027074 | 3.98 m ± 0.06 | 1970 | β+=100% |
| 158Tmm | 157.936979525 ± 0.000027074 | ~20 s | 1981 | IT ?; ε ? |
| 159Tm | 158.934975000 ± 0.00003 | 9.13 m ± 0.16 | 1971 | β+=100% |
| 160Tm | 159.935264177 ± 0.000035089 | 9.4 m ± 0.3 | 1970 | β+=100% |
| 160Tmm | 159.935264177 ± 0.000035089 | 74.5 s ± 1.5 | 1983 | IT=85±0.5%; β+=15±0.5% |
| 160Tmn | 159.935264177 ± 0.000035089 | ~200 ns | 1986 | IT=100% |
| 161Tm | 160.933549000 ± 0.00003 | 30.2 m ± 0.8 | 1959 | β+=100% |
| 161Tmm | 160.933549000 ± 0.00003 | 5 m [Estimated] | 1981 | β+ ?; IT ? |
| 161Tmn | 160.933549000 ± 0.00003 | 110 ns ± 3 | 1981 | IT=100% |
| 162Tm | 161.934001211 ± 0.000027974 | 21.70 m ± 0.19 | 1963 | β+=100% |
| 162Tmm | 161.934001211 ± 0.000027974 | 24.3 s ± 1.7 | 1974 | IT=81±0.4%; β+=19±0.4% |
| 163Tm | 162.932658282 ± 0.00000592 | 1.810 h ± 0.005 | 1959 | β+=100% |
| 163Tmm | 162.932658282 ± 0.00000592 | 380 ns ± 30 | 1975 | IT=100% |
| 164Tm | 163.933538019 ± 0.000026845 | 2.0 m ± 0.1 | 1960 | β+=100%; ε=61±0.1%; e+=39±0.1% |
| 164Tmm | 163.933538019 ± 0.000026845 | 5.1 m ± 0.1 | 1971 | IT≈80%; β+≈20% |
| 165Tm | 164.932441843 ± 0.000001779 | 30.06 h ± 0.03 | 1953 | β+=100% |
| 165Tmm | 164.932441843 ± 0.000001779 | 80 us ± 3 | 1967 | IT=100% |
| 165Tmn | 164.932441843 ± 0.000001779 | 9.0 us ± 0.5 | 1968 | IT=100% |
| 166Tm | 165.933562136 ± 0.000012401 | 7.70 h ± 0.03 | 1948 | β+=100% |
| 166Tmm | 165.933562136 ± 0.000012401 | 348 ms ± 21 | 1996 | IT=100% |
| 166Tmn | 165.933562136 ± 0.000012401 | 2 us ± 1 | 1995 | IT=100% |
| 167Tm | 166.932857206 ± 0.00000135 | 9.25 d ± 0.02 | 1948 | ε=100% |
| 167Tmm | 166.932857206 ± 0.00000135 | 1.16 us ± 0.06 | 1964 | IT=100% |
| 167Tmn | 166.932857206 ± 0.00000135 | 0.9 us ± 0.1 | 1965 | IT=100% |
| 168Tm | 167.934178457 ± 0.0000018 | 93.1 d ± 0.2 | 1949 | β+≈100%; β-=0.010±0.7% |
| 169Tm | 168.934218956 ± 0.000000792 | Stable | 1934 | IS=100% |
| 169Tmm | 168.934218956 ± 0.000000792 | 659.9 ns ± 2.3 | 1950 | IT=100% |
| 170Tm | 169.935807093 ± 0.000000785 | 128.6 d ± 0.3 | 1936 | β-=99.869±1%; ε=0.131±1% |
| 170Tmm | 169.935807093 ± 0.000000785 | 4.12 us ± 0.13 | 1967 | IT=100% |
| 171Tm | 170.936435162 ± 0.000001043 | 1.92 y ± 0.01 | 1948 | β-=100% |
| 171Tmm | 170.936435162 ± 0.000001043 | 2.60 us ± 0.02 | 1948 | IT=100% |
| 171Tmn | 170.936435162 ± 0.000001043 | 1.7 us ± 0.2 | 2009 | IT=100% |
| 172Tm | 171.938406959 ± 0.000005884 | 63.6 h ± 0.3 | 1956 | β-=100% |
| 172Tmm | 171.938406959 ± 0.000005884 | 132 us ± 7 | 2008 | IT=100% |
| 173Tm | 172.939606630 ± 0.000004723 | 8.24 h ± 0.08 | 1961 | β-=100% |
| 173Tmm | 172.939606630 ± 0.000004723 | 10.7 us ± 1.7 | 1972 | IT=100% |
| 173Tmn | 172.939606630 ± 0.000004723 | 250 ns ± 69 | 2012 | IT=100% |
| 173Tmp | 172.939606630 ± 0.000004723 | 121 ns ± 28 | 2012 | IT=100% |
| 174Tm | 173.942174061 ± 0.00004801 | 5.4 m ± 0.1 | 1960 | β-=100% |
| 174Tmm | 173.942174061 ± 0.00004801 | 2.29 s ± 0.01 | 2006 | IT≈100%; β-<1.5% |
| 174Tmn | 173.942174061 ± 0.00004801 | 106 us ± 7 | 2013 | IT=100% |
| 175Tm | 174.943842310 ± 0.000053677 | 15.2 m ± 0.5 | 1961 | β-=100% |
| 175Tmm | 174.943842310 ± 0.000053677 | 319 ns ± 35 | 2012 | IT=100% |
| 175Tmn | 174.943842310 ± 0.000053677 | 21 us ± 14 | 2012 | IT=100% |
| 176Tm | 175.946997707 ± 0.000107354 | 1.85 m ± 0.03 | 1961 | β-=100% |
| 177Tm | 176.948932 ± 0.000215 [Estimated] | 95 s ± 7 | 1989 | β-=100% |
| 177Tmm | 176.948932 ± 0.000215 [Estimated] | 77 s ± 11 | 1989 | β-=100% |
| 178Tm | 177.952506 ± 0.000322 [Estimated] | 10 s >300ns [Estimated] | 2008 | β- ?; β-n ? |
| 179Tm | 178.955018 ± 0.000429 [Estimated] | 18 s >300ns [Estimated] | 2012 | β- ?; β-n ? |
| 180Tm | 179.959023 ± 0.000429 [Estimated] | 3 s >300ns [Estimated] | 2012 | β- ?; β-n ? |
| 181Tm | 180.961954 ± 0.000537 [Estimated] | 7 s >300ns [Estimated] | 2012 | β- ?; β-n ? |
| 182Tm | 181.966194 ± 0.000537 [Estimated] | Not-specified | β- ?; β-n ? |
