Covalent Bonding

1
Covalent Bonding

• Last Bits

2
Coordinate Covalent Bond

• bond formed when
• 2 atoms share pair electrons but
• both electrons donated by same atom
• many polyatomics have coordinate covalent bonds
• must be able to recognize them

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Ammonium, NH41
Oh oh no electrons at all!
2 electrons just hanging around
4
Ammonium, NH41
Both electrons in this bond were donated by the N
atom
5
Hydronium, H3O
2 pairs of nonbonding electrons
6
Hydronium, H3O
Both electrons are provided by the oxygen atom
..
7
NETWORK SOLIDS Carbon

• Most covalent substances are molecular
• Carbon can form 4 bonds with 4 other C atoms
• Allows C to build up extensive network, like a
  crystal lattice
• Ex diamond
• Hard, nonconductors (except graphite)
• high mp bp, high Hf and Hv
• Strong covalent bonds hold atoms together

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Diamond Structure
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Network solids Silicon

• Silicon can also form network solids
• Ex quartz or SiO2
• Quartz has very complicated crystal structure