The first experiments were started in 1976 by a Soviet team led by Y. Oganessian at the Joint Institute for Nuclear Research at Dubna, who produced isotope Bohrium-261. With heavy nuclei of Chromium-54. In this experiment the was performed by bombarding of the fast rotating cylinder coated by a thin layer of Bismuth-204. By a tangentially directed stream of Chromium-54. German scientists have offered name Nielsbohrium.

In 1970 researchers led by Albert Ghiorso at the Berkeley Laboratory of the University of California by bombardment of californium with nitrogen ions and named Hahnium. Also this element was named Nielsbohrium.

Element Tantalum, Ta, Transition Metal. The discovery of transition metal tantalum. Symbolizing oxide is insoluble in acid, and was unable, just as the mythological Tantalos. Ekeberg called the ores in which tantalum. Was discovered tantalite and yttrotantalite. Perhaps Ekeberg isolated impure tantalum. Deep layers and upper mantle are poor by tantalum.

Element Tungsten, W, Transition Metal. Was produced by de Elhuyar brothers, students of Bergman in 1783. They named the new metal wolfram. After the mineral wolframite in which tungsten. Miners of 1416 centuries noticed that roasting of the ore tales the tin away, transferring it into slag.

Element Rhenium, Re, Transition Metal. Is the rarest and much dispersed trace element. Its average abundance is 7x10. Is the rarest element with stale isotopes.