The first 26 elements of the periodic table--from hydrogen to iron--formed inside stars during the process of nuclear fusion. The rest of the naturally occurring elements--cobalt, atomic number 27, through uranium, atomic number 92--arose through the incredible energy present in a supernova. But the periodic table doesn't end at 92--not even close. Last week the official tally reached 112 when the International Union of Pure and Applied Chemistry, the guardians of the table, after 13 years of discussion, welcomed element 112 into the fold.
While elements in the table higher than 92 have appeared in nature, such as the minuscule amounts of plutonium present in uranium deposits because of radioactive decay, most do not. They appear on Earth only when scientists create them, often by simulated fusion--slamming lighter elements into one another at high energy. The heaviest manmade elements are radioactive and highly unstable; they exist only fractions of a second before decaying or breaking apart, and they are only recognizable to scientists through computer readings of their radiation. Element 112, during its initial, tentative discovery in 1996, lasted a third of a millisecond before decaying into lighter elements. Thirteen years passed between the discovery of element 112, and its inclusion in the periodic table. In that span, scientists may have created even higher numbered elements--113, 114, 115, 116 and 118. But those elements could take years--or decades--to verify. For now, we have to stick with the decades-old, lab-made Promethiums and Americiums. Here are 10 of the coolest DIY elements researchers have ever created in a lab.
Back in the 1800s, Dmitri Mendeleev, the father of the periodic table, knew he had a problem--there was a gap at atomic number 43, between molybdenum and ruthenium. Mendeleev predicted some of the unknown element's properties based on its position in the table, but wouldn't live to see its official discovery.
That's because technetium is the lowest numbered element without a stable isotope--and because of its instability, it has never been found on the Earth. Italian physicists Carlo Perrier and Emilio Segre finally confirmed its existence in 1937, when they bombarded molybdenum with deuterium (heavy hydrogen) to create isotopes of technetium.
Promethium is the periodic table's other oddball, surrounded by stable elements but with no stable isotope itself. In 1941, Ohio State researchers irradiated neodymium and praseodymium, and their results showed properties that looked like that of element 61. However, 1940s technology couldn't extract rare earth metals from one another, so confirmation of the find took several more years.
Because they found the element through harnessing nuclear energy, promethium's founders named it after , the mythical figure who stole fire from heaven and gave it to mankind.
Neptunium and plutonium directly follow their planetary companion, uranium, on the periodic table. Appropriately so--scientists use uranium to create both. By bombarding uranium with neutrons, scientists at the University of California Berkeley created neptunium in 1940. Their neptunium then changed into plutonium through a process called , in which a neutron changes into a proton or vice versa (both variations also give off tiny particles to even out the charges). The next year they created the all-important plutonium-239 isotope, which provided the core of the "Fat Man" atomic bomb dropped on Nagasaki, Japan, during World War II.
Finding fermium was an accident--a team of American scientists discovered it in the debris of the United States' first , carried out in the Pacific in 1952, and named it after nuclear pioneer Enrico Fermi. The isotope they found, fermium-255, came about through 17 neutrons combined with uranium and went through eight beta decays. If you want to make the stuff without setting off a thermonuclear explosion, you have to go through a long chain of nuclear reactions and decays.
In 1944, some of the same scientists who discovered Fermium, went one step further. Bombarding plutonium-239 with neutrons created plutonium-240 and then plutonium-241; then beta decay turned one of those neutrons into a proton and they had the 95th element, americium, on their hands.
Seaborg's team picked "americium" because the continent across the pond already had "europium." Today the element shows up in many smoke detectors.
Like fermium and others, californium turned up in the fallout of the 1952 H-bomb test. However, californium does not need an H-bomb to be created. Two years earlier, Glenn Seaborg's team created californium-245 in 1950 by blasting curium with helium.
The most useful isotope is californium-252, which emits neutrons at an incredible rate--170 million per minute. This feature makes it extremely dangerous but also useful for analyzing the of authenticity gold and silver and for detecting metal fatigue, starting up nuclear reactors and finding land mines.
When more powerful particle accelerators came on the scene, scientists saw new ways to create high-energy elements. In 1974, scientists at the Lawrence Berkeley Lab used their Super-Heavy Ion Linear Accelerator to smash califorium-249 with oxygen-18 ions to create element 106. A Russian team claimed simultaneous credit for the discovery; creating it by crashing chromium into lead. The Berkeley group got the credit, however, and named the element after Glenn Seaborg.
While all the manmade elements are unstable, some have a half-life at least long enough for applications outside the lab. This is not the case for darmstadtium. Researchers in Darmstadt, Germany, spent a whole week in 1994 bombarding lead atoms with a billion billion (10 to the 18th power) ions of nickel. The result was one single atom of darmstadtium-269, which possessed a half-life of 0.17 milliseconds. The IUPAC recognized the group's find in 2001.
A team led by German Sigurd Hofmann at the Centre for Heavy Ion Research first created the element back in 1996 by fusing ions of zinc (element number 30) with lead (number 86) to create a nucleus with 112 protons. The atom decayed immediately, so Hofmann only knew what he had initially created by studying the energy emitted by decay.
Still, getting a new element onto the periodic table is slow going. The IUPAC requires independent confirmation of the find, but back in 1996, Hofmann says, "We were the leading laboratory, and to make element 112 was too difficult elsewhere." After a Japanese lab duplicated the finding in 2004, the review process began and, finally, last week, element 112 became a member of the club.