{"id":101,"date":"2020-04-08T15:04:07","date_gmt":"2020-04-08T15:04:07","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=101"},"modified":"2023-08-16T09:22:52","modified_gmt":"2023-08-16T09:22:52","slug":"technetium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/technetium\/","title":{"rendered":"Technetium (Tc)"},"content":{"rendered":"\n

Technetium is a chemical element with atomic number 43 in the periodic table. It\u2019s a synthetically produced element, but it can also be found in Earth\u2019s crust. The natural occurrence of element 43 is around 0.003 parts per trillion. <\/span><\/p>\n\n\n\n

As a member of the manganese<\/a> family of elements, technetium is a divalent transition metal. It\u2019s mainly used as a radioactive tracer in nuclear medicine, especially its technetium-99 isotope.\u00a0<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Technetium<\/span><\/h3>\n\n\n\n
Property<\/td>Value<\/td><\/tr>
Symbol<\/td>Tc<\/td><\/tr>
Name<\/td>Technetium<\/td><\/tr>
Atomic Number<\/td>43<\/td><\/tr>
Atomic Weight<\/td>(Not provided)<\/td><\/tr>
Group<\/td>7 (Transition metals)<\/td><\/tr>
Period<\/td>5 (d-block)<\/td><\/tr>
Color<\/td>Silver<\/a><\/td><\/tr>
Physical State<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>From 110 nanoseconds to 4.21 million years<\/td><\/tr>
Electronegativity<\/td>1.9<\/td><\/tr>
Density<\/td>11.5 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting Point<\/td>2157\u00b0C, 3915\u00b0F, 2430 K<\/td><\/tr>
Boiling Point<\/td>4262\u00b0C, 7704\u00b0F, 4535 K<\/td><\/tr>
Van der Waals Radius<\/td>0.128 nm<\/td><\/tr>
Ionic Radius<\/td>1.95 \u00c5<\/td><\/tr>
Isotopes<\/td>33<\/td><\/tr>
Most Characteristic Isotope<\/td>97Tc, 99Tc<\/td><\/tr>
Electronic Shell<\/td>[Kr] 4d\u20755s\u00b2<\/td><\/tr>
The Energy of the First Ionization<\/td>7.28 eV<\/td><\/tr>
The Energy of the Second Ionization<\/td>N\/A<\/td><\/tr>
Discovery Date<\/td>1937<\/td><\/tr>
Discovered By<\/td>Carlo Perrier and Emilio Segr\u00e8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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Located between the elements manganese and rhenium<\/a> on the periodic table, technetium has the symbol Tc, atomic number 43, atomic mass of (99) g.mol<\/span>-1<\/span>, and electron configuration [Kr] 4d<\/span>5<\/span>5s<\/span>2<\/span>. Element 43 is a silver metal with a hexagonal crystal structure. Its boiling point is 4262\u00b0C, 7704\u00b0F, 4535 K, while the melting point is achieved at 2157\u00b0C, 3915\u00b0F, 2430 K. This member of the manganese group of elements in the periodic table has an electronegativity of 1.9 according to Pauling, whereas the atomic radius according to van der Waals is 0.128 nm. <\/span><\/p>\n\n\n\n

Being classified as a transition metal, technetium is an excellent superconductor and a remarkable corrosion inhibitor. It also has strong paramagnetic properties. However, oxygen<\/a> exposure to the technetium metal may trigger a very slow process of tarnishing. Namely, it slowly tarnishes in moist air, while its powder form burns when exposed to O2. In addition, element 43 readily reacts with sulfuric acid, nitric acid, as well as with aqua regia. Technetium is not soluble in any concentration of hydrochloric acid.<\/span><\/p>\n\n\n\n

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

When the Japanese chemist Masataka Ogawa claimed to have discovered one of Mendeleev\u2019s predicted elements in 1908, no other scientist was able to confirm his scientific data. In this way,  \u2018eka-manganese\u2019 (technetium) was still left to be a puzzle to solve for the scientists of the world.<\/span><\/p>\n\n\n\n

The Contribution of Walter Noddack, Ida Tacke, and Otto Berg<\/span><\/h3>\n\n\n\n

In 1923, a team of German chemists that included the chemists Walter Noddack (1893-1960), Ida Tacke-Noddack (1896-1979), and Otto Berg attempted to discover the <\/span>two missing elements<\/span><\/a> of Mendeleev\u2019s periodic system of elements in a sample of molybdenum<\/a>. <\/span><\/p>\n\n\n\n

Employed at the Physikalisch-Technische Reichsanstalt (PTR) laboratory located in Berlin-Charlottenburg, Western Germany, these three scientists concluded that the elements with an odd-atomic number were less abundant than those with an even-atomic number. This led Noddack, Tacke, and Berg to the idea that they should look for the elusive <\/span>eka-manganese<\/span><\/i> element in platinum<\/a> and columbite ores because many rare elements have already been traced in these particular ores. Before embarking on the projected goal, Tacke took a whole year to first study the chemical separation procedures required for their research mission. <\/span><\/p>\n\n\n\n

After thorough preparation and following Mosley’s new concept for classification of elements, the German team of scientists identified the elements 43 (<\/span>masurium<\/span><\/i>, today named as <\/span>technetium<\/span><\/i>), and 75 <\/span>(rhenium<\/span><\/i>). Unfortunately, Noddack, Tacke, and Berg were unable to reproduce the methods that led them to the discovery of element 43. The reason behind their failure to confirm the previously obtained scientific evidence was that element 43 had no stable isotopes. They also needed a <\/span>particle accelerator<\/span><\/a> for their confirmation research which hadn\u2019t been invented until 1929. <\/span><\/p>\n\n\n\n

The Discovery of Emilio Segr\u00e8 <\/span><\/h3>\n\n\n\n

In 1937, the Italian-American physicist and Nobel laureate Emilio Segr\u00e8 (1905-1989) together with the Italian mineralogist Carlo Perrier (1886-1948) led a group of Italian scientists at the University of Palermo, Sicily, Italy, throughout the investigation of a deflector foil segment from a molybdenum-made cyclotron. This particle accelerator was previously used to smash atoms of molybdenum by deuterons at the Berkeley Laboratories in California, United States. <\/span><\/p>\n\n\n\n

Segr\u00e8 and Perrier exposed the sample to high-energy radiation, the two scientists discovered a different color line on the spectrum, which pointed out the presence of a new chemical element. After they managed to isolate one ten-billionth of a gram, they analyzed the properties of the new element and concluded that it belongs to the gap of element 43, as predicted by Mendeleev.\u00a0<\/span><\/p>\n\n\n\n

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

The name is derived from the Greek word ‘<\/span>technetos<\/span><\/i>‘ meaning artificial because technetium is the first element that has been artificially produced. However, minuscule amounts of element 43 can still be traced in nature.<\/span><\/p>\n\n\n\n

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

In 1952, the American astronomer and specialist in spectroscopy <\/span>Paul W. Merrill<\/span><\/a> (1887-1961) detected the presence of element 43 in the S-type, M-type, and N-type stars of our Universe by analyzing the light they produce. Its natural occurrence is almost non-existent. For this reason, technetium today is mainly produced from the spent nuclear fuel rods in large quantities. <\/span><\/p>\n\n\n\n

However, in 1962, two chemists employed at the Department of Chemistry, University of Arkansas, Fayetteville, United States, succeeded in what then seemed impossible – isolating the elusive element from a terrestrial material. By observing an African pitchblende sample (a uranium<\/a>-rich ore) as a spontaneous fission product of uranium-238, B.T. Kenna and P.K. Kuroda detected <\/span>the first naturally occurring isotope of technetium<\/span><\/a> – 99Tc.\u00a0<\/span><\/p>\n\n\n\n

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

Until the present, only minuscule amounts of this radioactive chemical element have some form of application, which can be observed in the instances given below:<\/span><\/p>\n\n\n\n