Structures+-+Melissa


 * __// Describe the structure of and bonding in Silicon and Silicon Dioxide //__**

**Silicon**

-Silicon atoms form 4 equivalent covalent bonds which are arranged tetrahedrally.This forms a giant tetrahedral structure. -Have high melting and boiling points because of strong covalent bonds. -Hard and insoluble in water -Semi conductor

**Silicon Dioxide** -Silicon dioxide has a chemical formula of **SiO2** and is most commonly known as silica. Silica is most commonly found in nature as sand or quartz and is mainly used to produce glass. -Each silicon has equal covalent bonds to 4 oxygen atoms, tetrahedrally distributed. -Each oxygen atom makes equal bonds with 2 silicon atoms, therefore the ratio of a silicon dioxide molecule is 2:4 or 1:2 -Structure is held together by strong covalent bonds, hence melting and boiling points are high


 * Both Silicon and Silicon Dioxide have a 3D giant covalent structure, same as in Diamond. **
 * Both structures are held together by strong covalent bonds. **


 * [[image:150px-Glass_tetrahedon.png width="205" height="185"]] **