Coordinate covalent bonds involve one atom contributing both electrons to form a bond that cannot be distinguished from a regular covalent bond. Metallic bonds are depicted by the electron sea model where positive metal ions are immersed in a sea of delocalized and mobile electrons. Network covalent solids have atoms bonded covalently forming very hard, high melting point materials that are poor conductors such as diamond. Allotropes of carbon include diamond, graphite, amorphous carbon, fullerenes, carbon nanotubes, buckyballs, and lonsdaleite which each have different bonding structures and properties.

1. COORDINATE COVALENT Coordinate covalent bond -a covalent bond in which one atom contributes both electrons -once such bond is formed we cannot tell it from regular covalent bond Example: HCl + NH3 forms NH4Cl

3. METALLIC BONDS -Electron Sea Model -pictures a solid metal as a network of positive ions immersed in “sea of electrons” -electrons in the sea are free (not attached to any particular ion) and they are mobile.

4. NETWORK COVALENT SOLIDS Solids in which all the atoms are Bonded covalently. Properties: Very hard Very high mp Poor thermal and electrical conductors Example: C (diamond)

5. Allotropes of Carbon

6. Allotropes of Carbon Diamond is one of the best known allotropes of carbon. useful for both industrial applications and jewelry. hardest known natural mineral. dominant industrial use is in cutting, drilling, grinding (diamond edged cutters), and polishing.

8. Unlike diamond, graphite is an electrical conductor.

9. the most stable form of carbon.

10. Graphite powder is used as a dry lubricant.

12. some short-range order can be observed, but there is no long-range pattern of atomic positions..

14. Allotropes of Carbon Soot- also known as black carbon, is the second-leading cause of global warming after carbon dioxide a black, carbonaceous substance produced during incomplete combustion of coal, wood, oil, etc.

16. are molecules of varying sizes composed entirely of carbon, which take the form of a hollow sphere, ellipsoid, or tube

18. Allotropes of Carbon Glassy carbon or vitreous carbon is a class of non-graphitizing carbon widely used as an electrode material in electrochemistry, as well as for high temperature crucibles and as a component of some prosthetic devices

19. Allotropes of Carbon Carbon nanofoam -consists of a low-density cluster-assembly of carbon atoms strung together in a loose three-dimensional web

20. Allotropes of Carbon Carbon nanobuds newly discovered allotrope of carbon in which fullerene like "buds" are covalently attached to the outer sidewalls of the carbon nanotubes. has useful properties of both fullerenes and carbon nanotubes

21. Allotropes of Carbon Lonsdaleite -hexagonal allotrope of the carbon allotrope diamond believed to form from graphite present in meteorites upon their impact to Earth. diamond but retains graphite's hexagonal crystal lattice