The chemical formula for silicon dioxide, also called silica, is SiO2. Silicon and oxygen are two of the most abundant elements in the Earth's crust, with silica composing 59 percent. When exposed to oxygen, silicon surfaces oxidize to form the compound SiO2.
In nature, silica can be seen as sand or quartz. Synthetically, silica is used as a semiconductor in circuits. Silica has a high melting point of about 1,600 degrees Celsius or 2,912 degrees Fahrenheit. Because it can withstand temperature fluctuations, it is used in many electronic devices. Other uses include glass production, ceramics and fiber optics, as well as in heat-resistant cooking utensils. Silicon dioxide is important in the process of making cement and concrete. Silicon can be produced by heating sand and carbon to temperatures about 2,200 degrees Celsius.
SiO2 can also be found naturally in plant foods and multivitamin supplements. Silicon dioxide is crucial for the development of bones, skin and nails in humans. Nutritionists recommend a trace amount, about 5 to 10 milligrams, of SiO2 per day. Foods that contain this compound include fruits and vegetables, sunflower seeds, whole grains and nuts, according to New Health Guide. Silicon dioxide should not make up more than 2 percent of the food's weight.