{"id":238,"date":"2020-04-09T10:08:27","date_gmt":"2020-04-09T10:08:27","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=238"},"modified":"2023-08-15T14:40:15","modified_gmt":"2023-08-15T14:40:15","slug":"californium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/californium\/","title":{"rendered":"Californium (Cf)"},"content":{"rendered":"\n

Californium is a radioactive chemical element with the symbol Cf and atomic number 98 in the periodic table of elements<\/a>. It\u2019s a synthetically produced element, hence it cannot be found in Earth\u2019s crust. Being a member of the actinides family of periodic table elements, californium\u2019s molecular structure can be divalent or trivalent. <\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Californium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Cf<\/td><\/tr>
Atomic number<\/td>98<\/td><\/tr>
Atomic weight (mass)<\/td>251.00 g.mol-1<\/td><\/tr>
Group (number)<\/td>N\/A (Actinides)<\/td><\/tr>
Period<\/td>7<\/td><\/tr>
Color<\/td>Silvery-white<\/td><\/tr>
Physical state<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>Variable<\/td><\/tr>
Electronegativity according to Pauling<\/td>1.3<\/td><\/tr>
Density<\/td>15.1 g.mol-1 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>900\u00b0C, 1652\u00b0F, 1173 K<\/td><\/tr>
Boiling point<\/td>Unknown<\/td><\/tr>
Van der Waals radius<\/td>N\/A<\/td><\/tr>
Ionic radius<\/td>N\/A<\/td><\/tr>
Isotopes<\/td>10<\/td><\/tr>
Most characteristic isotope<\/td>249Cf, 252Cf<\/td><\/tr>
Electronic shell<\/td>[Rn] 5f10 7s2<\/td><\/tr>
The energy of the first ionization<\/td>608 kJ\/mol<\/td><\/tr>
The energy of the second ionization<\/td>1145.4<\/td><\/tr>
Discovery date<\/td>In 1950 by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn T. Seaborg<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With an atomic mass of 251.00 g.mol -1, and electron configuration [Rn] 5f<\/span>10<\/span>7s<\/span>2<\/span>, californium is a man-made, highly radioactive actinide. Together with berkelium<\/a> and einsteinium<\/a>, californium is one of the heaviest elements in the periodic table<\/a>. It\u2019s so malleable and soft that it can be easily cut with a sharp object. This radioactive metal reaches its melting point at 900\u00b0C (1652\u00b0F, 1173 K), while its boiling point is unknown. Californium has a +3 oxidation state and an electronegativity of 1.3 according to Pauling. <\/span><\/p>\n\n\n\n

Its atomic radius according to van der Waals is still unknown. In addition, californium shares its properties with the three previous actinides in the periodic table (americium<\/a>, curium<\/a>, and berkelium), as well as with the three actinides that are assigned in the periodic table after it (einsteinium, fermium<\/a>, and mendelevium<\/a>).       <\/span><\/p>\n\n\n\n

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

In 1950, a team of scientific researchers at the Lawrence Berkeley National Laboratory in Berkeley, California, attempted to bombard curium-242 with alpha particles of helium<\/a> ions in a 60-inch cyclotron. This procedure was followed by chemical separation of the resulting californium-245 and a free neutron from the other elements by a method called chromatography.<\/span><\/p>\n\n\n\n

In this way, the American chemists Stanley Gerald Thompson (1912 – 1976), Kenneth Street Jr. (1920-2006), Albert Ghiorso (1915-2010), and Glenn Theodore Seaborg (1912 – 1999) succeeded in producing a new element – californium – at the University of California, Berkeley. <\/span><\/p>\n\n\n\n

In 1958, Thompson and the research associate at the University of Chicago’s Metallurgical Laboratory, Burris Cunningham, managed to isolate larger quantities of the pure elemental form of californium by neutron irradiation of plutonium<\/a>-239 which lasted for five years. Their scientific attempt resulted in the production of 1.2 micrograms of californium. <\/span><\/p>\n\n\n\n

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

Since this radioactive chemical element was synthesized at the University of Berkeley, California, it was conveniently named in honor of the University in the state of California. Glen T. This pattern of naming new chemical elements after the location of their discovery was not novel by any stretch of the imagination, though. <\/span><\/p>\n\n\n\n

For instance, terbium <\/a>was named after the biggest quarry containing this substance, located in the Swedish village of Ytterby; americium was named in parallel to the element above it – europium<\/a>, and so on.  <\/span><\/p>\n\n\n\n

However, this naming approach turned out to be impractical when it came to californium. Since the equivalent lanthanide for californium was the chemical element dysprosium<\/a>, meaning \u2018hard to get\u2019 in Greek, the team of researchers went with the name of the location where the new lanthanide was discovered. <\/span><\/p>\n\n\n\n

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

Despite being a man-made chemical element, it is believed that californium also results from supernovae. However, not being available in nature, this radioactive substance is produced in scientific laboratories via nuclear processes. After the discovery of this chemical element which resulted in traceable amounts, weighable quantities of the californium-252 isotope were produced in 1954. Nowadays, the Oak Ridge National Laboratory in Tennessee produces 25mg of this radioactive substance per year on average using a high flux isotope reactor (HFIR). <\/span><\/p>\n\n\n\n

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

Being a strong neutron emitter, californium is widely used in:<\/span><\/p>\n\n\n\n