In 1976 a Soviet team led by Y. Oganessian at the Joint Institute for Nuclear Research at Dubna bombarded bismuth-209 atoms with chromium-54 ions to produce an isotope with mass number 261 and a half-life of 1–2 msec. In 1981 a German research team led by P. Armbruster and G. Münzenberg at the Institute for Heavy Ion Research at Darmstadt also bombarded bismuth-209 atoms with chromium-54 ions. By reducing the temperature of the target atoms, the Germans were able to produce and unambiguously identify an isotope of element 107 having mass number 262 and a half-life of 5 msec. The Germans suggested the name nielsbohrium, which the Soviets had suggested be given to element 105 (dubnium), to honor the Danish physicist Niels Bohr. The most stable isotope, bohrium-270, has a half-life of 61 sec.
In 1994 a committee of the International Union of Pure and Applied Chemistry (IUPAC), convened to resolve naming disputes for the transactinide elements, recommended that element 107 be named bohrium
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