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Metal > GoldAu - Gold A precious metal. Once used only for money and ornimentation, gold has found many uses in modern technology. The free metal is not very reactive and is often found in electronics and micromechanics. Compounds, notably the chloride, are used in archival photoprocessing and analytical chemistry. Gold is not used in experiments at Phoenix College. Atomic number - 79 Density g/mL 19 .3 Atomic weight u 196 .9665 Melting point K 1337 .58 Bonding radius A 1 .34 Boiling point K 3130 Atomic radius A 1 .79 Heat of vaporization kJ/mol 334 .4 Ionization Potential V 9 .225 Heat of fusion kJ/mol 12 .55 Electronegativity - 2 .54 Specific heat J/gK 0 .128 The oxide is amphoteric. Crystal are face centered cubic. Electron config. : [Xe] 4f14 5d10 6s1 USES OF GOLD One of the principal uses of gold today is as a currency reserve--usually stored in the form of gold bricks weighing 13 kg (35 troy lb). Gold was for centuries used directly as currency along with silver. During the 19th century it assumed a role as the sole basis of the currencies of most nations; paper MONEY was directly convertible into gold. World War I disrupted this system. The original GOLD STANDARD was gradually abandoned (the United States stopped minting gold coinage in 1934), and the dollar eventually emerged as the principal unit of international monetary transactions. Since the 1970s gold has been bought and sold on the market, with widely fluctuating prices, and gold reserves maintain only a very indirect relationship with the values of currencies. There is a large and rapidly growing demand for gold in industrial processes. Its relatively high electrical conductivity and extremely high resistance to corrosion make the metal critically important in micro-electrical circuits. Minute quantities dissolved in glass or plastic sheets prevent the passage of infrared radiation and make an efficient heat shield. Because of its chemical stability, gold is in demand for bearings used in corrosive atmospheres. It is also plated on surfaces exposed to corrosive fluids or vapors. Its lack of toxicity and its compatibility with living systems make it indispensable in dentistry and medicine, and its beauty has made it outstanding in the arts and crafts since ancient times.
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