Special physical properties of the element tin:

Appearance and allotropes: Tin is a silvery-white metal with a faint light-blue lustre, and it has three allotropes - white tin, grey tin and brittle tin. White tin is stable between 13.2 °C and 161 °C, crystallises in the tetragonal system, is soft and extremely malleable, and can be rolled into very thin tin foil; grey tin is stable below 13.2 °C, crystallises in the diamond cubic system, is powdery and has no metallic lustre; brittle tin is stable above 161 °C, crystallises in the orthorhombic system, and is hard, brittle and poor in malleability.

Melting point and boiling point: Tin melts at 231.9 °C and boils at 2270 °C. It is a low-melting-point metal, which makes it easy to melt and handle when heated and gives it wide use in soldering and alloy manufacturing.

Density and ductility: Tin has a density of 7.3 g/cm³, with good malleability but poor ductility. Its malleability is at its best at 100 °C, when it can be beaten into very thin tin foil for packaging cigarettes, confectionery and similar goods to protect them from moisture.

Electrical and thermal conductivity: Tin conducts both electricity and heat well, so it is widely used in electronics and electrical engineering - for example in making solder, in joining electronic components and in manufacturing circuit boards.

Magnetism: Tin is a non-magnetic metal, unaffected by and not attracted to magnetic fields. This makes it advantageous in special applications where magnetic interference must be avoided, such as certain components in electronic devices.

Special chemical properties of the element tin:

Oxidation behaviour: At room temperature tin is relatively stable chemically and is not easily oxidised by oxygen; a dense protective film of tin dioxide forms on its surface and prevents further oxidation, so tin keeps its silvery-white lustre and does not readily rust or corrode. Under heating, however, the reaction between tin and oxygen speeds up and more tin dioxide is formed.

Valency: Tin can be divalent or tetravalent, and it exists in compounds as Sn(II) or Sn(IV). Tetravalent tin compounds are more stable than divalent ones, so divalent tin compounds (such as stannous salts) are strongly reducing and are easily oxidised to tetravalent tin compounds (such as stannates).

Reaction with acids: Tin is stable towards water. It dissolves slowly in dilute acids (such as dilute hydrochloric acid or dilute sulfuric acid) and more quickly in concentrated acids. For example, tin reacts with concentrated hydrochloric acid to give stannous chloride and hydrogen, and with concentrated sulfuric acid to give stannous sulfate, sulfur dioxide and water. Tin also dissolves in strong alkali solutions (such as sodium hydroxide solution) to form stannite and hydrogen.

Reaction with halogens: Tin reacts rapidly with all the halogens (chlorine, bromine and iodine), forming tin tetrahalides under heating (such as tin tetrachloride and tin tetrabromide). These tin halides have important applications in organic synthesis and chemical analysis.

Reaction with sulfur: Tin reacts with sulfur to form tin sulfides (such as stannous sulfide and tin disulfide). Tin sulfide is an important tin ore and is widely used in metallurgy and the chemical industry. For example, stannous sulfide can be used to refine metallic tin, and tin disulfide can be used as a golden pigment.

Reaction with oxidising agents: Tin can be oxidised to tetravalent tin compounds by oxidising agents such as lead nitrate and hydrogen peroxide. For example, tin reacts with lead nitrate to form a tetravalent tin compound and metallic lead, and with hydrogen peroxide to form a divalent tin compound and oxygen.