Main Difference – Silicon vs Silica
Silicon and silica are two terms often used in inorganic chemistry. Silicon is the second most abundant element on the earth, second only to oxygen. Thus, it is very important to know the difference between silicon and silica. The main difference between silicon and silica is that silicon is an element whereas silica is a compound.
Key Areas Covered
Key Terms: Inorganic Chemistry, Oxygen, Polymorphs, Quartz, Semiconductor, Silica, Silicon, Silicones
What is Silicon
Silicon is an element found in earth crust abundantly. In the periodic table, silicon is a member of group 14 and is categorized as a semi-metal or a metalloid. This is because silicon show some properties of both metals and non-metals.
The atomic number of silicon is 14, and Silicon is positioned in p-block. The electron configuration of silicon is [Ne]3s23p2. Since there are only two electrons in p orbitals of silicon, it can provide space for four more incoming electrons. Therefore, silicon can form maximum of four covalent bonds. The melting point of silicon is about 14140C. Silicon has three stable isotopes; 28Si, 29Si, and 30Si.
Silicon is a semiconductor. It has so many important applications in electronic industry since it is a good conductor of electricity. Silicon is also used in the synthesis of polymers called silicones. Silicon does not occur as a free element in nature. It always occurs as a mineral with a combination of other elements.
What is Silica
Silica is a compound made out of silicon and oxygen atoms. Silica is the name given for silicon dioxide. The molecular formula of silica is SiO2. Therefore, silica is made out of two most abundant elements on earth. Silica is found as quartz in nature. Silica is also the major constituent of sand.
Under normal temperature and pressure, silica is a solid. Pure silica is a colorless crystalline compound having a high melting point. The melting point of silica is about 1713oC. Molar mass of silica is about 60 g/mol. Silica is obtained mostly by mining of quartz.
Although silica is called silicon dioxide, the crystalline structure of silica shows that silicon atom is surrounded by four oxygen atoms attached through single covalent bonds. This is because this tetrahedral structure is more stable.
Silica structure is a stable structure, but it is attacked by hydrofluoric acid (HF) to form hexafluorosilicate acid. This reaction is given below.
SiO2 + 6HF → H2SiF6 + 2H2O
Silica is used in the production of glass. Silica beads are also used in chromatographic applications.
Silica occurs in a number of crystalline forms. These forms are called polymorphs. Examples for these polymorphs include α-quartz, β-quartz, coesite, etc.
Difference Between Silicon and Silica
Silicon: Silicon is an element found in the earth crust.
Silica: Silica is a compound made out of silicon and oxygen atoms.
Silicon: Silicon is a single element.
Silica: Silica is composed of silicon and oxygen atoms.
Silicon: Melting point of silicon is about 14140C.
Silica: Melting point of silica is about 17130C.
Silicon: Silicon is a semiconductor which can conduct electricity.
Silica: Silica is not capable of conducting electricity.
Silicon: Silicon does not occur alone in nature.
Silica: Silica can occur as a pure compound.
Silicon: The crystal structure of silicon is brittle.
Silica: The crystal structure of silica is very hard.
Both silicon and silica contains silicon atoms. But silica is different from silicon due to their structures and properties. The main difference between silicon and silica is that silicon is an element whereas silica is a compound.
1.”Chemistry of Silicon (Z=14).” Chemistry LibreTexts. Libretexts, 20 June 2017. Web. Available here. A30 June 2017.
2.”Silica.” Encyclopædia Britannica. Encyclopædia Britannica, inc., n.d. Web. Available here. 30 June 2017.