Mercury is a chemical element with the symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum (from Greek 'hydr-' water and 'argyros' silver). A heavy, silvery d-block element, mercury is the only metal that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. With a freezing point of 38.83 C and boiling point of 356.73 C, mercury has one of the narrowest ranges of its liquid state of any metal. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion, a pure form of mercuric sulfide, is mostly obtained by reaction of mercury (produced by reduction from cinnabar) with sulfur. Cinnabar is highly toxic by ingestion or inhalation of the dust.
Contributions by Darrien, Mav, and Femto.
Chemistry answer: Hg. Source: Wolfram|Alpha