Chemical formula: Sn

Mbth: tin

Atomic weight: 1 18.438+0.

Period: 5

Introduction: Tin is a famous "hardware"-one of gold, silver, copper, iron and tin. As early as ancient times, people discovered and used tin. In some ancient tombs in China, tin pots, tin candlesticks and other tin utensils are often excavated. According to research, during the Zhou Dynasty in China, the use of tin ware was very common. Tin daily necessities were also found in ancient tombs in Egypt. China is rich in tin resources, especially Gejiu, a world-famous "tin capital". In addition, Guangxi, Guangdong and Jiangxi provinces also produce tin. 1800 The annual output of tin in the world was only 4,000 tons, 1900 was 85,000 tons, and 1940 was 250,000 tons. Now it has exceeded 600,000 tons. But arsenic is associated with tin, and its compound is the main component of arsenic.

I. Classification of Tin

(1) white tin: tetragonal system, unit cell parameters: a=0.5832nm, c=0.3 18 1nm, with 4 Sn atoms in the unit cell, density of 7.28 g/cm3, hardness of 2, and good ductility;

(2) Gray tin: rhombic cubic system, unit cell parameter: a=0.6489nm, and there are 8 Sn atoms in the unit cell with a density of 5.75 g/cm3;

(3) Brittle tin: orthorhombic system with density of 6.54g/cm3.

Second, physical properties.

(1) melting point: 23 1.89℃

(2) Boiling point: 2260℃

(3) Mohs hardness: 1.5

(4) solubility: slightly soluble in water

(5) Color: slightly blue-white luster.

Third, chemical properties.

(1) A protective film of tin dioxide is formed on the surface of tin in air, which is stable and accelerates the oxidation reaction when heated.

(2) Tin reacts with halogen under heating to generate tin tetrahalide.

(3) can react with sulfur

(4) Tin is stable to water, and can be dissolved slowly in dilute acid and rapidly in concentrated acid.

(5) Tin can be dissolved in alkaline solution; It will be corroded in acidic solution of ferric chloride, zinc chloride and other salts.

(6) The chemical properties of tin are very stable, and it is not easy to be oxidized by oxygen at room temperature.

Fourth, the purpose

(1) metallic tin is mainly used to make alloys.

(2) Tin sulfide, a compound of tin and sulfur, is similar in color to gold and is often used as a gold pigment.

(3) Tin dioxide, compounds of tin and oxygen. Tin is not oxidized in air at room temperature, but becomes tin dioxide when heated strongly. Tin dioxide is a white powder insoluble in water, which can be used to make enamel, white glaze and opalescent glass.

(4) The material of tin ware is alloy, in which the content of pure tin is above 97%, and it does not contain lead, so it is suitable for daily use.

(5) Tin is the fourth precious metal after platinum, gold and silver. Glossy, non-toxic, not easy to be oxidized and discolored, with good sterilization, purification and preservation effects. Commonly used in food preservation, canned food inner anti-corrosion film and so on.

(6) Tin is a soft metal with low melting point and strong plasticity. It can have a variety of surface treatment processes, and can be made into a variety of styles of products, including traditional elegant European wine utensils, candlesticks, noble and generous tea sets, and even eye-catching vases and exquisite table ornaments, which can be comparable to sparkling silverware.

In ancient China, tin was often used to make bronze.