platinumgoldmercury
Ag

Au

Rg
Appearance
metallic yellow
General properties
Name, symbol, number gold, Au, 79
Pronunciation /ˈɡld/
Element category transition metal
Group, period, block 116, d
Standard atomic weight 196.966569(4)
Electron configuration [Xe] 4f14 5d10 6s1
Electrons per shell 2, 8, 18, 32, 18, 1 (Image)
Physical properties
Phase solid
Density (near r.t.) 19.30 g·cm−3
Liquid density at m.p. 17.31 g·cm−3
Melting point 1337.33 K, 1064.18 °C, 1947.52 °F
Boiling point 3129 K, 2856 °C, 5173 °F
Heat of fusion 12.55 kJ·mol−1
Heat of vaporization 324 kJ·mol−1
Molar heat capacity 25.418 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1646 1814 2021 2281 2620 3078
Atomic properties
Oxidation states -1, 1, 2, 3, 4, 5
(amphoteric oxide)
Electronegativity 2.54 (Pauling scale)
Ionization energies 1st: 890.1 kJ·mol−1
2nd: 1980 kJ·mol−1
Atomic radius 144 pm
Covalent radius 136±6 pm
Van der Waals radius 166 pm
Miscellanea
Crystal structure Lattice face centered cubic
Magnetic ordering diamagnetic
Electrical resistivity (20 °C) 22.14 nΩ·m
Thermal conductivity 318 W·m−1·K−1
Thermal expansion (25 °C) 14.2 µm·m−1·K−1
Speed of sound (thin rod) (r.t.) 2030 m·s−1
Tensile strength 120 MPa
Young's modulus 79 GPa
Shear modulus 27 GPa
Bulk modulus 180 GPa
Poisson ratio 0.44
Mohs hardness 2.5
Vickers hardness 216 MPa
Brinell hardness 25 HB MPa
CAS registry number 7440-57-5
Most stable isotopes
Main article: Isotopes of gold
iso NA half-life DM DE (MeV) DP
195Au syn 186.10 d ε 0.227 195Pt
196Au syn 6.183 d ε 1.506 196Pt
β 0.686 196Hg
197Au 100% 197Au is stable with 118 neutrons
198Au syn 2.69517 d β 1.372 198Hg
199Au syn 3.169 d β 0.453 199Hg
· r

References