Copper subgroup trends

Copper subgroup PHYSICAL PROPERTIES

Copper, silver and gold are soft lustred metals. Copper is red, gold has yellow colour. These metals are ductile that can be easily rolled and form very thin wire and foil (Au can be rolled to foil of the thickness about 0.2 mm and 1g of Au can be transformed to wire of the length 2 km!).

Metals of copper subgroup have high electric and thermal conductivity.

Silver has lower melting and boiling points comparing with Cu and Au and it is the most electro- and thermally conductive metal simultaneously. These facts are explained by the unique stability of completely filled 4d orbital. The single valence electron of Ag is not capable to penetrate through it. It is this stability that the most stable oxidation state of Ag is +1.

All three have been used for making coins. Hence they are often named collectively the coinage metals. Copper subgroup elements are constituents of various metal alloys. Of great practical importance are bronzes (90% Cu, 10% Sn), tombac (90% Cu, 10% Zn), cupronicke l [мельхіор] (68% Cu, 30% Ni, 1% Mn, 1% Fe), German silver [нейзильбер] (65% Cu, 20% Zn, 15% Ni), brass [латунь] (60% Cu, 40% Zn), and also coin alloys (95% Cu, 5% Al – 5 copecs coins in the former USSR, 80% Cu, 20% Ni in 10 copecs coins and more).

Copper subgroup trends

	Cu	Ag	Au
density, g/сm^3	8.94	10.5	19.3
tm, ^oС
tb, ^oС
Rа, nm	0.123	0.144	0.144
radius Е^+, nm	0.096	0.116	0.137
Ionisation energy Е ® Е^+, еV
Е^o(Е^3++ 3е = Е), V	+0.340	+0.799	+1.500
	Cu^2+/Cu	Ag^+/Ag	Au^3+/Au

Дата добавления: 2015-07-25