{"id":283,"date":"2020-04-09T10:15:17","date_gmt":"2020-04-09T10:15:17","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=283"},"modified":"2023-08-15T13:25:43","modified_gmt":"2023-08-15T13:25:43","slug":"terbium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/terbium\/","title":{"rendered":"Terbium (Tb)"},"content":{"rendered":"\n

Terbium is a chemical element with the atomic number 65 in the periodic table. It\u2019s one of the least plentiful rare-earth metals that occur in Earth\u2019s crust. Located between the elements gadolinium<\/a> and dysprosium<\/a>, terbium is classified as a member of the lanthanide series of the periodic table. This rare-earth metal has three valence electrons and is mainly used in phosphors.\u00a0<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Terbium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Tb<\/td><\/tr>
Atomic number<\/td>65<\/td><\/tr>
Atomic weight (mass)<\/td>158.925 g.mol-1<\/td><\/tr>
Group (number)<\/td>Lanthanides<\/td><\/tr>
Period<\/td>6 (f-block)<\/td><\/tr>
Color<\/td>Silvery-gray<\/td><\/tr>
Physical state<\/td>Solid at 20\u00b0C<\/td><\/tr>
Half-life<\/td>From 0.94(+33\u221222) milliseconds to 180 years<\/td><\/tr>
Electronegativity according to Pauling<\/td>1.2<\/td><\/tr>
Density<\/td>8.23 g.cm-3<\/td><\/tr>
Melting point<\/td>1359\u00b0C, 2478\u00b0F, 1632 K<\/td><\/tr>
Boiling point<\/td>3230\u00b0C, 5846\u00b0F, 3503 K<\/td><\/tr>
Van der Waals radius<\/td>Unknown<\/td><\/tr>
Ionic radius<\/td>Unknown<\/td><\/tr>
Isotopes<\/td>36<\/td><\/tr>
Most characteristic isotope<\/td>159Tb<\/td><\/tr>
Electronic shell<\/td>[Xe]4f96s2<\/td><\/tr>
The energy of the first ionization<\/td>563.5 kJ.mol-1<\/td><\/tr>
The energy of the second ionization<\/td>1109.6 kJ.mol-1<\/td><\/tr>
Discovery date<\/td>In 1843 by Carl Gustav Mosander<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol Tb, atomic number 65, atomic mass of 158.925 g.mol<\/span>-1<\/span>, and electron configuration [Xe]4f<\/span>9<\/span>6s<\/span>2<\/span>, terbium is a soft, ductile, malleable, silvery-gray metal that can be dented with any hard object. It reaches its boiling point at 3230\u00b0C, 5846\u00b0F, 3503 K, while the melting point is achieved at X1359\u00b0C, 2478\u00b0F, 1632 K. This member of the lanthanides family of elements 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

Terbium is a highly reactive chemical. When exposed to high temperatures, terbium metal reacts with many elements, especially with carbon<\/a>, arsenic<\/a>, and silicon. Compared to the other lanthanides, element 65 can maintain a relatively stable electron configuration upon exposure to air. <\/span><\/p>\n\n\n\n

Element 65 occurs in three different structural modifications (crystal allotropes). When exposed to a temperature below -54.15oC\/-65.47oF\/219 K, Tb adopts ferromagnetic properties that become antiferromagnetic if the temperature rises above the aforementioned temperature. Terbium metal is a very strong paramagnet above \u221243\u00b0C\/\u221246\u00b0F\/230 K.<\/span><\/p>\n\n\n\n

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

Familiar with the fact that the rare-earth elements almost always occur within the same type of ore, the Swedish chemist Carl Gustav Mosander (1797 – 1858) attempted to study the mineral <\/span>gadolinite<\/span><\/i>. He was intrigued to perform new experiments on this particular mineral after the discovery of the Finnish chemist and physicist Johan Gadolin (1760 – 1852). Namely, in 1794 the Finnish scientist had succeeded in tracing the element yttrium<\/a> as an impurity in the substance labeled as yttria (yttrium oxide, Y<\/span>2<\/span>O<\/span>3<\/span>.) that was contained in the yttrium mineral. <\/span><\/p>\n\n\n\n

By using ammonium hydroxide, Mosander precipitated fractions of different basicity from the yttria mineral sample. In these fractions, the Swedish chemist detected two previously unknown differently colored substances that he labeled as <\/span>erbia<\/span><\/i> (a rose pink erbium<\/a> oxide) and <\/span>terbia<\/span><\/i> (a yellow-colored terbium oxide).\u00a0<\/span><\/p>\n\n\n\n

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

The discoverer of terbium, Carl Gustav Mosander, named the new element 65 <\/span>terbium<\/span><\/i> after the village of Ytterby in Sweden, where the mineral source of this chemical element was obtained from.\u00a0<\/span><\/p>\n\n\n\n

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

Terbium has an occurrence of approximately 1.2 mg\/kg in Earth\u2019s crust. It can often be traced together with other rare-earth elements in mineral ores, such as monazite (reddish-brown phosphate), xenotime (phosphate mineral), bastnasite (three carbonate fluoride mineral), cerite, and euxenite (brownish-black mineral). <\/span><\/p>\n\n\n\n

The pure form of terbium metal is prepared by a metallothermic reduction of the anhydrous fluoride with calcium<\/a> metal. <\/span><\/p>\n\n\n\n

The largest terbium ore mines in the world are located in the United States, India, Sri Lanka, Brazil, and Australia. For commercial purposes, terbium is mainly obtained from the ion-adsorption clays of Southern China by ion exchange, solvent extraction, electrolysis, or reduction.\u00a0<\/span><\/p>\n\n\n\n

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

Element 65 is one of the rarest earth metals which is also difficult to be isolated from the mineral ores. For this reason, the terbium extraction process from the minerals is very expensive. The high cost of this substance also limits its everyday use. <\/span><\/p>\n\n\n\n

The following are some of the instances where the practical terbium application can be observed:<\/span><\/p>\n\n\n\n