The key difference between silica and silicon dioxide is that the silica is the common name of SiO2 whereas silicon dioxide is the IUPAC name of SiO2. Moreover, silicon dioxide refers to the purest form only while silica can be either pure or impure form.
Both terms “silica” and “silicon dioxide” refers to the same chemical compound, but they are different in the usage of these terms. The term silica is a common name, and we use it mainly in the chemical industry while the term silicone dioxide is the chemical name of the same compound that we use, mostly in chemistry.
What is Silica?
Silica is the common name of SiO2. This is a major constituent on earth’s crust; the earth’s crust has around 59% this compound. This compound occurs in three main forms as quartz, tridymite and cristobalite. Moreover, silica is a mineral that occurs naturally in sandstones, clay and granite. It also occurs in various living organisms as well.
What is Silicon Dioxide?
Silicon dioxide is the IUPAC name of SiO2. This term explains that this compound is an oxide of silicon. We use this term to name the purest form of SiO2. It occurs in quartz and as components in living organisms. The molar mass is 60.08 g/mol. It appears as a transparent solid. The melting point and boiling points are 1,713 °C and 2,950 °C respectively.
The silicon dioxide molecules show a tetrahedral geometry. There, four oxygen atoms surround a silicon atom. Moreover, this compound has many crystalline forms; we call them polymorphs. There are some amorphous forms as well. Apart from that, we can convert silicon dioxide into silicon via a reduction reaction with carbon.
There are many uses of silicon dioxide. We use it for the production of Portland cement, for sand casting, in hydraulic fracturing, as a precursor to produce glass, to make optical fibres for telecommunication, as a food additive, etc.
What is the Difference Between Silica and Silicon Dioxide?
Silica is the common name of SiO2. We can use this term to name either pure or impure SiO2. Silicon dioxide is the IUPAC name of SiO2. Therefore, it is the chemical name of that compound. This is the key difference between silica and silicaon dioxide. Moreover, we use silicaon dioxide to name only the purest form of SiO2. Furthermore, the visually distinguishable difference between silica and silicaon dioxide is their colour. Most of the times, silica has a pale yellow colour due to the presence of impurities. Whereas, silicaon dioxide is transparent and appears as a white solid because of its high purity.
Summary – Silica vs Silicon Dioxide
Both terms silica and silicon dioxide names the same chemical compound. However, the use of these terms is different from each other according to the place where we use them. The difference between silica and silicon dioxide is that silica is the common name of SiO2 whereas silicon dioxide is the IUPAC name that we use to name only the purest form of SiO2.
1. Britannica, The Editors of Encyclopaedia. “Silica.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 25 Feb. 2018. Available here
2. “Silicon Dioxide.” Wikipedia, Wikimedia Foundation, 16 Aug. 2018. Available here