Transition metal prevent d–d bonding, which again tends to differentiate them from the accepted transition metals. Mercury has a melting point of and is a liquid at room temperature. Transition metal In chemistry, the term transition metal (or transition element) has three possible meanings: English chemist Charles Bury (1890–1968) first used the word "transition" in this context in 1921, when he referred to a "transition series of elements" during the change of an inner layer of electrons (for example n=3 in the 4th row of the periodic table) from a stable group of 8 to one of 18, or from 18 to
Room-temperature superconductor predicted that it may be possible to raise the critical temperature to above 0 °C and achieve room-temperature superconductivity. Previously the record was held by the cuprates, which have demonstrated superconductivity at atmospheric pressure at temperatures as high as , and under high pressure. Although some researchers doubt whether room-temperature superconductivity is actually achievable, superconductivity has repeatedly been discovered at temperatures that were previously unexpected or held to be impossible. Claims of "near-room temperature" transient effects date from the early 1950s and some suggest that in fact the breakthrough might have been made more than once but could not be