Covalent Bonding a few extra concepts

Coordinate Covalent Bond bond formed when: 2 atoms share pair electrons but both electrons donated by same atom many polyatomic ions have coordinate covalent bonds must be able to recognize them

H .. + H : N : H H+1 .. oh oh – no electrons at all! 2 non-bonding electrons just hanging around will join together in a bond and form an ion

Ammonium, NH4+1 +1 H .. H : N : H .. H both electrons in this bond were donated by the N atom in ammonia NH4

.. + H : O : H H+1 .. Hydronium, H3O+1 2 pairs of non-bonding e- zero electrons

Hydronium, H3O+1 +1 H both electrons are provided by the oxygen atom in water (H2O) .. H : O : H ..

NETWORK SOLIDS carbon and silicon form extensive networks, similar to a crystal lattice different physical properties than molecular compounds: hard rather than soft (except graphite) high mp & bp, high Hf & Hv similar physical properties than molecular cmpds: non-conductors

NETWORK SOLIDS: Carbon most covalent substances are molecular carbon forms 4 bonds with 4 other C atoms allows C to build up extensive network ex: diamond, graphite strong covalent bonds hold atoms together

Diamond Structure

Network solids: Silicon silicon can also form network solids ex: quartz (SiO2) quartz has very complicated crystal structure