Pure Mercury / Hg:
Mercury is a chemical element with the symbol Hg and atomic number80. It is also known as quicksilver or hydrargyrum (from "hydr-"water and "argyros" silver). A heavy, silvery d-block element,mercury is the only metal that is liquid at standard conditions fortemperature and pressure; the only other element that is liquidunder these conditions is bromine, and metals such as caesium,francium, gallium, and rubidium melt just above room temperature.With a freezing point of -38.83 celsius and boiling point of 356.73celsius, mercury has one of the narrowest ranges of its liquidstate of any metal. Mercury occurs in deposits throughout the worldmostly as cinnabar (mercuric sulfide). The red pigment vermilion ismostly obtained by reduction from cinnabar. Cinnabar is highlytoxic by ingestion or inhalation of the dust. Mercury poisoning canalso result from exposure to water-soluble forms of mercury (suchas mercuric chloride or methylmercury), inhalation of mercuryvapor, or eating seafood contaminated with mercury. Mercury is usedin thermometers, barometers, manometers, sphygmomanometers, floatvalves, some electrical switches, and other scientific apparatus,though concerns about the element''s toxicity have led to mercurythermometers and sphygmomanometers being largely phased out inclinical environments in favor of alcohol-filled, galinstan-filled,digital, or thermistor-based instruments. It remains in use inscientific research applications and in amalgam material for dentalrestoration. It is used in lighting: electricity passed throughmercury vapor in a phosphor tube produces short-wave ultravioletlight which then causes the phosphor to fluoresce, making visiblelight.