From Wikipedia, the free encyclopedia. The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2.It is found in nature in several forms, including quartz and opal. In fact, silica has 17 crystalline forms.he chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2.
Windsor is home to 217,188 people, according to the 2016 census. Windsor's population has grown by three per cent in the past five years, but the city still fell behind the national growth rate, according to data collected during the 2016 census.
windsor ËwÉªnzÉr is a town and unparished area in the royal borough of windsor and maidenhead in berkshire england it is widely known as the site of windsor castle one of the official residences of the british royal family the town is situated 23 miles 37 km west of charing cross london