Lead
Generalities :
Lead is a metal used for more than 2 000 years. It originates from mines and is extracted mainly in the form of galena (PbS). In 2013 the mining production represents only 45% of the world production. Indeed the sectors of recycling of lead are very efficient.
It is a rather soft, rather poor conductor metal and a good sound-insulating material. Lead is the material of choice in the protection against ionizing sources thanks to its rather big pit, high density and the fact that it is easy to produce.
Used pure, it is water-insoluble but soluble in nitric acid and in hot sulphuric acid.
It is a dangerous material when inhaled or ingested. It can cause diseases filed together under the name of Lead poisoning.
Physical properties :
Natural state : solid
Color : blue-grey
Chemical symbol : Pb
Density : 11,35
Melting point : 327 °C
Boiling point : 1 740 °C
Atomic mass : 207,2 g / mol
Atomic number (number of protons of the pit) : 82