Silicon is a chemical element, its chemical symbol is Si, formerly known as silicon. Atomic number 14, relative atomic mass 28.09, there are amorphous and crystalline allotropes, amorphous silicon and crystalline silicon allotropes. A metal-like element belonging to the IVA group on the periodic table. Crystalline silicon is steel gray, amorphous silicon is black, density 2.4g/cm3, melting point 1420ºC, boiling point 2355ºC, crystalline silicon belongs to atomic crystal, hard and shiny, with semiconductor properties. Silicon has relatively active chemical properties and can be combined with oxygen and other elements at high temperature. It is insoluble in water, nitric acid and hydrochloric acid, but soluble in hydrofluoric acid and alkaline liquor. It is used for making alloys such as ferrosilicon and silicon steel. Silicon is very widely distributed in nature, about 27.6% in the earth’s crust, mainly in the form of silica and silicate exist in the form of crystalline silicon is dark blue, very brittle, is a typical semiconductor. Chemical properties are very stable. At room temperature, it is difficult to react with other substances except hydrogen fluoride.

Types	Chemical synthesis(%)
	≥	≤	≤
	Si	Al	C	S	P
ferrosilicon75#	75	1.5	0.2	0.02	0.04
ferrosilicon72#	72	2.0	0.2	0.02	0.04
ferrosilicon65#	65	2.0	0.2	0.02	0.04