Mercury - Hg General Information Discovery Mercury was known to ancient civilisations, such as the Chinese and Hindus, and has been found in Egyptian tombs of 1500 B.C. Appearance Mercury is a heavy, silvery, liquid metal. Source Mercury occurs very rarely free in nature, but can be found in ores, principally cinnabar. This is mostly found in Spain and Italy, which together produce about 50% of the world's supply of this element. The metal is obtained by heating cinnabar in a current of air and condensing the vapour. Uses Mercury easily forms alloys, called amalgams, with other metals such as gold, silver and tin. Its ease in amalgamating with gold is made use of in recovering gold from its ores. It is used in the manufacture of sodium hydroxide and chlorine by the electrolysis of brine. The metal is widely used in making advertising signs, mercury switches and other electrical apparatus. It is used in laboratory work for making thermometers, barometers, diffusion pumps and many other instruments. Other uses are in pesticides, dental work, batteries and catalysts. Because of its toxicity, all these uses of mercury are being phased out or are under review. Some mercury salts and organic mercury compounds are still important, including mercurous chloride (calomel) which is used in electrolysis, and mercuric sulfide (vermilion), a high-grade paint pigment. Biological Role Mercury has no known biological role. It is a virulent poison, readily absorbed through the respiratory tract, the gastrointestinal tract or through the skin. It is a cumulative poison and dangerous levels are readily attained in air. It is now always handled with the utmost care. General Information Mercury is stable with air and water, unreactive to all acids except nitric acid, and all alkalis. It is a rather poor conductor of heat compared with other metals, and a fair conductor of electricity.

	Physical Information
	Atomic Number		80
	Relative Atomic Mass (12C=12.000)		200.59
	Melting Point/K		234
	Boiling Point/K		629
	Density/kg m-3		13546 (293K)
	Ground State Electron Configuration		[Xe]4f145d106s2
	Electron Affinity(M-M-)/kJ mol-1		+18

	Key Isotopes
	nuclide	196Hg	197Hg	198Hg	199Hg	200Hg
	atomic mass	195.97		197.97	198.97	199.97
	natural abundance	0.2%	0%	10.1%	17.0%	23.1%
	half-life	stable	65 h	stable	stable	stable
	nuclide	201Hg	202Hg	204Hg
	atomic mass	200.97	201.97	203.97
	natural abundance	13.2%	29.6%	6.8%
	half-life	stable	stable	stable

Other Information
Enthalpy of Fusion/kJ mol-1		2.33
Enthalpy of Vaporisation/kJ mol-1		59.1
Oxidation States
main	Hg+2
others	Hg+1

	Ionisation Energies/kJ mol-1
	M - M+	1007
	M+ - M2+	1809
	M2+ - M3+	3300
	M3+ - M4+	4400
	M4+ - M5+	5900
	M5+ - M6+	7400
	M6+ - M7+	9100
	M7+ - M8+	11600
	M8+ - M9+	13400
	M9+ - M10+	15300