Mercury Mercury is a metallic element that is a liquid at room temperature, it is one of the transition elements. Mercury's atomic number is 80. It is superconductive when cooled to within a few degrees of absolute zero. Mercury was once known as liquid silver or quicksilver which was studied by the alchemists. Mercury was first distinguished as an element by the French chemist Antoine Laurent Lavoisier in his experiment on the composition of air. At room temperature mercury is a shining, moving liquid that has a silvery-white color, and slightly volatile. Mercury remains a liquid over a wide temperature rang