Properties of Silicon Dioxide-
 Formula  SiO2
 Molar Mass  60.0843 g
Melting Point

1710 (oC)

Boiling Point

2230 (oC)

Density ~2.6 g/C3
Natural Abundance in Solar System 4.47x107 mg/kg
Natural Abundance In the earth’s crust 2.82x105 mg/kg
Natural Abundance in the sea 2.2 mg/l
Percent Composition by Mass 47.644% Si
53.255% O
Percent Composition by Number 33.33% Si
66.66% O

Quartz Crystal

     Silicon Dioxide, also commonly know as silica, is an interesting compound. Silicon Dioxide is commonly found as a white or transparent, crystalline solid. It is an odorless compound. It belongs to group IV of the chemical family called metal oxides. It is a very stable compound, as in the only acid it will react with is hydrofluoric acid. Silicon dioxide is an acidic oxide. It is acidic because when in water it produces hydrogen ions from the water. Silicon dioxide also transmits visible and ultraviolet light.

    Silicon Dioxide comes in many different geometrical patterns. 35 crystalline shapes have been observed which results in differing density of each group of atoms. When the first atomic bomb test run was dropped in New Mexico it produced another crystalline form of silicon dioxide known as ketite. Quartz is one of the most common shapes. These geometric crystalline shapes can transform when silicon dioxide is heated over 867 oC. Silicon dioxide is held together by double, covalent bonds.

Si(s)+ 2O(g)àSiO2

    In the equation above silicon react with 2 oxygen atoms to form Silicon Dioxide. In this case the silicon ion is an ion with the valence of +4 and each of the two oxygen anions have a valence of –2.