{"id":271,"date":"2020-04-09T10:12:33","date_gmt":"2020-04-09T10:12:33","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=271"},"modified":"2023-08-15T13:38:08","modified_gmt":"2023-08-15T13:38:08","slug":"thulium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/thulium\/","title":{"rendered":"Thulium (Tm)"},"content":{"rendered":"\n

Thulium is a chemical element with atomic number 69 in the periodic table. It is found in Earth\u2019s crust in almost the same quantities as the elements iodine<\/a> and antimony<\/a>, with an occurrence of around 500 parts per million. <\/span><\/p>\n\n\n\n

Being a member of the lanthanide series of periodic table elements, this rare earth metal has three valence electrons. Thulium is present in the human body as a trace amount in the kidneys, the liver, and the bones. Despite having limited practical use, thulium isotopes are most beneficial in nuclear medicine.<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Thulium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Tm<\/td><\/tr>
Atomic number<\/td>69<\/td><\/tr>
Atomic weight (mass)<\/td>168.934 g.mol-1<\/td><\/tr>
Group (number)<\/td>Lanthanides<\/td><\/tr>
Period<\/td>6 (f-block)<\/td><\/tr>
Color<\/td>A bright, silvery metal at room temperature<\/td><\/tr>
Physical state<\/td>Solid at 20\u00b0C<\/td><\/tr>
Half-life<\/td>From 3.1(3) milliseconds to 1.92 years<\/td><\/tr>
Electronegativity according to Pauling<\/td>1.2<\/td><\/tr>
Density<\/td>9.3 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>1545\u00b0C, 2813\u00b0F, 1818 K<\/td><\/tr>
Boiling point<\/td>1950\u00b0C, 3542\u00b0F, 2223 K<\/td><\/tr>
Van der Waals radius<\/td>Unknown<\/td><\/tr>
Ionic radius<\/td>1.59 (+1) \u00c5<\/td><\/tr>
Isotopes<\/td>34<\/td><\/tr>
Most characteristic isotope<\/td>169Tm<\/td><\/tr>
Electronic shell<\/td>[Xe] 4f136s2<\/td><\/tr>
The energy of the first ionization<\/td>595.3 kJ.mol-1<\/td><\/tr>
The energy of the second ionization<\/td>1160.7 kJ.mol-1<\/td><\/tr>
The energy of the third ionization<\/td>2284 kJ.mol-1<\/td><\/tr>
Discovery date<\/td>In 1879 by Per Teodor Cleve<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol Tm, atomic number 69, relative atomic mass of 168.934  g.mol<\/span>-1<\/span>, and electron configuration X, thulium is a moderately soft and ductile metal with bright, silvery color and a close-packed hexagonal structure. It reaches its boiling point at 1950\u00b0C, 3542\u00b0F, 2223 K, while the melting point is achieved at 1545\u00b0C, 2813\u00b0F, 1818 K. This member of the lanthanide family of elements in the periodic table has an electronegativity of 1.2 according to Pauling, whereas the atomic radius according to van der Waals is unknown. <\/span><\/p>\n\n\n\n

When exposed to temperatures above 56 K (\u2212217\u00b0C, or \u2212359\u00b0F), thulium becomes a strong paramagnet. On the other hand, exposure to temperatures between 56 and 32 K (\u2212241\u00b0C, or \u2212402\u00b0F) give thulium metal antiferromagnetic properties, while below 32 K (-241.15\u00b0C, or -402.07\u00b0F) thulium adopts the characteristics of a ferrimagnet.<\/span><\/p>\n\n\n\n

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How Was Thulium Discovered?<\/span><\/h2>\n\n\n\n

Being familiar with the fact that many of the rare earth elements were obtained from a yttrium<\/a> sample, Per Teodor Cleve was conducting his research experiments on an erbia (erbium<\/a> oxide) sample in his laboratory at the University of Uppsala, Sweden. Cleve believed that the elements isolated from this mineral are further contaminated with traces of new rare earth elements. And \u2013 he was right.<\/span><\/p>\n\n\n\n

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The Discovery of Per Teodor Cleve<\/span><\/h3>\n\n\n\n

After the elements erbium and terbium<\/a> were extracted from yttrium in 1843, this Swedish chemist explored the erbium oxide more closely to confirm his scientific conviction. His dedicated work resulted in the discovery of element 69, i.e. thulium (Tu) in 1879.<\/span><\/p>\n\n\n\n

In fact, it wasn\u2019t just thulium that he discovered. His experiments produced two new substances \u2013 a green and a brown one. Cleve labeled the green substance as \u2018<\/span>thulia<\/span><\/i>\u2019 (thulium oxide), while the brown one turned out to be \u2018<\/span>holmia<\/span><\/i>\u2019, i.e. an oxide of holmium<\/a> (element 67).<\/span><\/p>\n\n\n\n

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The Contribution of Charles James<\/span><\/h3>\n\n\n\n

In 1911, the British-American researcher Charles James succeeded in isolating the pure, elemental form of thulium by performing 15.000 recrystallizations of the thulium bromate compound.\u00a0<\/span><\/p>\n\n\n\n

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How Did Thulium Get Its Name?<\/span><\/h2>\n\n\n\n

Element 69 was named \u2018<\/span>thulium<\/span><\/i>\u2019 after Thule, the ancient name for Scandinavia. By proposing the name of a mythological region also known as <\/span>Ultima Thule<\/span><\/i>, the discoverer of thulium honored his native country.\u00a0<\/span><\/p>\n\n\n\n

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Where Can You Find Thulium?<\/span><\/h2>\n\n\n\n

All rare-earth elements occur alongside other rare-earth elements (lanthanides) in nature, and so does thulium. Small quantities of this chemical element can be traced in the minerals <\/span>monazite <\/span><\/i>(0.007% of thulium occurrence) and <\/span>bastnasite<\/span><\/i> (0.0008% of thulium occurrence). Thulium also occurs in the minerals gadolinite,<\/span> xenotime, and euxenite. <\/span><\/p>\n\n\n\n

The largest mining locations of thulium ores in the world can be found in China, Australia, United States, Brazil, India, and Sri Lanka.\u00a0<\/span><\/p>\n\n\n\n

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Thulium in Everyday Life<\/span><\/h2>\n\n\n\n

Element 69 is largely used in medicine, but it can be also applied in other industrial branches:<\/span><\/p>\n\n\n\n