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Gold - Properties and Uses - Supplier Data by Goodfellow

Background

Gold has been known since prehistoric times.

It is a soft metal with a characteristic yellow colour. Gold is the most malleable and ductile of any element. It is unaffected by air, water, alkalis and acids, with the exception of “aqua regia”, HNO3/HCl. The fact that it is chemically unreactive means that it is often found in its natural state. Gold is a good thermal and electrical conductor and has excellent reflective properties to both light and infrared. It has an abundance in the earth’s crust of 0.0011 ppm.

Most of the metal is retained for use as bullion reserves, but some is used within the electronics and jewellery industries, where it is frequently alloyed with other elements to improve the mechanical properties of the metal (e.g. copper and silver). Other uses for Gold are as a heat reflecting coating for glass as well as as a decorative medium.

Key Properties

The key properties of Gold are tabulated below.

Table 1. Key properties

Atomic Properties

 

 

 

Atomic number

79

Atomic radius - Goldschmidt ( nm )

0.144

Atomic weight ( amu )

196.9665

Crystal structure

Face centred cubic

Electronic structure

Xe 4f14 5d10 6s1

Photo-electric work function ( eV )

4.8

Thermal neutron absorption cross-section ( Barns )

98.8

Valences shown

1,3

Ionisation Potential

No.

eV

 

 

1

9.22

 

 

2

20.5

 

Natural Isotope Distribution

Mass No.

%

 

 

197

100

 

Electrical Properties

 

 

 

Temperature coefficient ( K-1 )

0.0040 @ 0-100

Electrical resistivity ( µOhm.cm )

2.20 @ 20

Thermal emf against Pt (cold 0°C - hot 100°C) ( mV )

+0.74

Mechanical Properties

 

Material condition

Soft

Hard

Polycrystalline

Bulk modulus ( GPa )

 

 

171

Hardness - Vickers

20-30

60

 

Poisson's ratio

 

 

0.42

Tensile modulus ( GPa )

 

 

78.5

Tensile strength ( MPa )

130

220

 

Yield strength ( MPa )

 

205

 

Physical Properties

 

 

 

Boiling point (°C )

3080

Density ( g.cm-3 )

19.30 @ 20

Melting point (°C )

1064.4

Thermal Properties

 

 

 

Coefficient of thermal expansion ( x10-6 K-1 )

14.1 @ 0-100

Latent heat of evaporation ( J.g-1 )

1738

Latent heat of fusion ( J.g-1 )

64.9

Specific heat ( J.K-1.kg-1 )

129 @ 25

Thermal conductivity ( W.m-1.K-1 )

318 @ 0-100

About Goodfellow

Goodfellow supplies metals, ceramics and other materials to meet the research, development and specialist production requirements of science and industry worldwide.

 

 

Source: Goodfellow.

 

For more information on this source please visit Goodfellow.

 

Date Added: May 5, 2003 | Updated: Jun 11, 2013
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