Published: 24 January, 2001

Controversy over Element 105

Specifically, we have paperwork that gives different names for several of the new elements: Db for number 105 instead of Ha and Bh for number 107 instead of Ns. Do we have names for 110, 111, or beyond? What is the last one that was made?

By the end of April 1970, a group of scientists working in Dubna in the Soviet Union claimed to have synthesized a new element, Element 105. Soon after, a competing group working in Berkeley, California produced Element 105 by another route. The American group later showed that they had made Element 105 one year earlier (but didn't notice it in their data until later!), and further claimed that they were unable to reproduce the work of the Soviet scientists (implying that they had lied!). The first group to discover an element gets to propose the name; the Berkeley group proposed naming Element 105 hahnium, in honor of the German scientist Otto Hahn. Because of the controversy over who discovered Element 105, the name was not settled until 1997!

Element 107 was initially discovered in 1981 by a team of researchers in Darmstadt, Germany; I have not been able to confirm that your symbol of Ns ever represented this element, or what it stood for.

The following names were finally accepted in 1997: Element 105, Dubnium (named after the city of Dubna, Russia in which the element was discovered in 1970, symbol Db); Element 106, Seaborgium (named in honor of Glenn Seaborg, symbol Sg, discovered 1970); Element 107, Bohrium (named in honor of Neils Bohr, symbol Bh, discovered 1981); Element 108, Hassium (named after the German province of Hesse in which the element was discovered in 1984, symbol Hs), and Element 109, Meitnerium (named in honor of Lise Meitner, symbol Mt, discovered 1982). A New York Times article describing the naming of the recently discovered elements can be found at www.periodic.lanl.gov/naming.html

Element 110 (discovered November 1994), Element 111 (discovered December 1994), Element 112 (discovered February 1996), Element 114 (October 1997), and Element 116 and Element 118 (discovered June 1999) have been observed but have not yet been named. Elements 113, 115, and 117 have not been made yet, nor has any element with atomic number greater than 118.

These very heavy atoms do not occur naturally. It takes dozens of people years of effort to make them in the laboratory. And even then the process is slow. For example, the team making Element 118 did not make much at all – only 3 atoms over the course of eleven days! The atoms were made by crashing a beam of krypton atoms into lead atoms, and each atom lasted only one one-thousandth of a second.

References: the Chemical Rubber Company, Handbook of Chemistry and Physics, 71st Edition (1990-1991) on Element 105, and the web-site of the American Institute of Physics and the American Physics Society on later elements.