{"id":295,"date":"2020-04-09T10:17:58","date_gmt":"2020-04-09T10:17:58","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=295"},"modified":"2023-08-15T13:09:10","modified_gmt":"2023-08-15T13:09:10","slug":"promethium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/promethium\/","title":{"rendered":"Promethium (Pm)"},"content":{"rendered":"\n

Promethium is a chemical element with the atomic number 61 in the periodic table. Although it\u2019s an artificially produced substance that cannot be found in Earth\u2019s crust, promethium can also occur in trace amounts in the uranium ores. <\/span><\/p>\n\n\n\n

Element 61 is classified as a member of the lanthanides family of the periodic table. This highly radioactive and artificially produced rare-earth metal has three valence electrons in its outer shell that may participate in the formation of a chemical bond. Promethium is mainly used for scientific purposes and research. <\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Promethium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Pm<\/td><\/tr>
Atomic number<\/td>61<\/td><\/tr>
Atomic weight (mass)<\/td>(147) g.mol-1<\/td><\/tr>
Group (number)<\/td>Lanthanides<\/td><\/tr>
Period<\/td>6 (f-block)<\/td><\/tr>
Color<\/td>Silvery-white metallic substance<\/td><\/tr>
Physical state<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>From 0.5 seconds to 17.7 years<\/td><\/tr>
Electronegativity according to Pauling<\/td>Unknown<\/td><\/tr>
Density<\/td>6.475 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>1042\u00b0C, 1908\u00b0F, 1315 K<\/td><\/tr>
Boiling point<\/td>3000\u00b0C, 5432\u00b0F, 3273 K<\/td><\/tr>
Van der Waals radius<\/td>Unknown<\/td><\/tr>
Ionic radius<\/td>Unknown<\/td><\/tr>
Isotopes<\/td>38<\/td><\/tr>
Most characteristic isotope<\/td>145Pm, 147Pm<\/td><\/tr>
Electronic shell<\/td>[Xe] 4f5 6s2<\/td><\/tr>
The energy of the first ionization<\/td>534.6 kJ.mol-1<\/td><\/tr>
The energy of the second ionization<\/td>1050 kJ.mol-1<\/td><\/tr>
Discovery date<\/td>In 1945 by Jacob .A. Marinsky, Lawrence E. Glendenin, and Charles D. Coryell<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol Pm, atomic number 61, atomic mass of X g.mol-1, and electron configuration [Xe] 4f<\/span>5<\/span> 6s<\/span>2<\/span>, promethium is a highly radioactive rare-earth metal that emits beta radiation. It reaches its boiling point at 3000\u00b0C, 5432\u00b0F, 3273 K, while the melting point is achieved at 1042\u00b0C, 1908\u00b0F, 1315 K. <\/span><\/p>\n\n\n\n

While promethium does not display ferromagnetic properties, it does respond to an external magnetic field which makes this element somewhat magnetic. Metallic promethium is silvery-white in color. On the other hand, its radioactivity makes it radiate with a pale blue or green glow in the dark.   <\/span><\/p>\n\n\n\n

There are two allotropes of promethium:<\/span><\/p>\n\n\n\n