Tin is obtained by reducing the ore with coal in a reverberatory furnace. Ordinary tin is composed of nine stable isotopes. Thirteen unstable isotopes are also known. Ordinary tin is a silvery white metal, is malleable, somewhat ductile, and has a highly crystalline structure. The element has two or perhaps three allotropic forms.
White tin has a tetragonal structure.
When tin is cooled below 13.20C, it changes slowly from white to gray. This change is affected by impurities, such as aluminum and zinc, and can be prevented by small additions of antimony or bismuth. There are few if any uses for gray tin. Tin takes a high polish and is used to coat other metals to prevent corrosion or other chemical action. Such tin plate over steel is used in the so-called tin can for preserving food.