CHEM 2120U Lecture Notes - Lecture 8: Scanning Tunneling Microscope, Stanley Miller, Trigonal Planar Molecular Geometry
Document Summary
Carbon occurs in nature in a surprising variety of structures. One of these elemental forms, diamond, consists of an extended, regularly repeating arrangement of sp3-hybridized carbon atoms. Their tetrahedral shape yields an extended network of strong covalent carbon-carbon single bonds that extends three-dimensionally from one end of the diamond to the other. A diamond is essentially a single (giant) molecule, whose interlocking array of bonds gives it extreme hardness and mechanical strength. A particularly interesting form of elemental carbon is graphene. All the carbon atoms of graphene are sp2 hybridized. The trigonal planar shape at each carbon atom yields a chicken wire network of repeating hexagons of carbon that extends in two dimensions, rather than across three dimensions as in diamond. This sheet of carbon atoms could consist of vast numbers of carbon atoms, yet it is only one atom thick!
