beryllium
Beryllium is a chemical element belonging to the alkaline earth metal. Its symbol is Be and its atomic number is 4. It is present at room temperature as a lightweight, hard, brittle gray metal. 2 tend to be cations and are not found in pure form in nature, and are mainly produced from beryl and stearic acid. In the universe, the life of beryllium produced by star nucleus synthesis is short, so its existence rate is very small. When beryllium is mixed with metals such as aluminum, copper, iron, and nickel, alloys can be used to improve various physical properties. It has a specific gravity of 1.85, which is light and hard, and has high thermal conductivity. It is used in aerospace fields such as missiles, spaceships and satellites, electric / electronic, nuclear power, and alloy. However, exposure to beryllium is toxic and may cause symptoms such as beryllium poisoning.