Element (104)

Element 104 (unnilquadium), chemical element, symbol (Unq); for physical constants see Periodic Table. The name of this element is temporary, proposed by the International Union of Pure and Applied Physics. In 1964, Soviet workers at the Joint Institute for Nuclear Research at Dubna (USSR) produced what they claimed was isotope²⁶⁰ 104, by bombarding plutonium-242 with neon-22 ions. In 1969, scientists working under Albert Ghiorso at the University of California at Berkeley reported that they were unable to reproduce the work of the Dubna group but had produced isotopes of element 104, with mass numbers 257 and 259104 among them, by bombarding californium- 249 with carbon-12 and carbon-13 ions. The names kurchatovium and rutherfordium have been proposed.