Simplify the following text for a Grade 9 native English-speaking person.
Original: Today , silicon is purified by converting it to a silicon compound that can be more easily purified by distillation than in its original state , and then converting that silicon compound back into pure silicon . Trichlorosilane is the silicon compound most commonly used as the intermediate , although silicon tetrachloride and silane are also used .
Simplified: Sand is a compound of silicon known as silicon dioxide or silica .