Gold

Symbol: Au
Atomic Number: 79
Atomic Weight: 196.96654
Element Classification: Transition Metal
Discovered By: Known to the ancients.
Discovery Date: n/a (Unknown)
Name Origin: Anglo-Saxon: geolo (yellow); symbol from Latin: aurum (shining dawn).

Density (g/cc): 19.3
Melting Point (K): 1337.58
Boiling Point (K): 3080
Appearance: Soft, malleable, yellow metal
Atomic Radius (pm): 146
Atomic Volume (cc/mol): 10.2
Covalent Radius (pm): 134
Ionic Radius: 85 (+3e) 137 (+1e)
Specific Heat (@20C J/g mol): 0.129
Fusion Heat (kJ/mol): 12.68
Evaporation Heat (kJ/mol): ~340
Thermal Conductivity (@25C W/m K):
Debye Temperature (K): 170.00
Pauling Negativity Number: 2.54
First Ionizing Energy (kJ/mol): 889.3
Oxidation States: 3, 1
Electronic Configuration: [Xe] 4f14 5d10 6s1
Lattice Structure: Face-Centered Cubic (FCC)
Lattice Constant (): 4.080
Lattice C/A Ratio: n/a

Mineral Hardness [no units]: 2.5
Brinell Hardness [/MN m-2]: 2450
Vickers Hardness [/MN m-2]: 216

Note: Pure gold is very soft and the most malleable metal known. Alloys, which are more commonly encountered, are harder and somewhat easier to prepare. Gold is difficult to etch. Relatively few metallographers work with precious metals, other than those used in electronic devices.

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