Liquid the distances between the molecules become smaller. When the liquid reaches its freezing point the molecules will usually lock into a very specific order, called crystallizing, and the bonds between them become more rigid, changing the liquid into its solid state (unless supercooling occurs). Only two elements are liquid at standard conditions for temperature and pressure: mercury and bromine. Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium. Metal alloys that are liquid at room temperature include NaK, a sodium-potassium metal alloy, galinstan, a fusible alloy liquid, and some amalgams (alloys involving mercury). Pure
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