Covalent Bonding Last Bits

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

H .. + H : N : H H+1 .. Ammonium, NH4+1 Oh oh – no electrons at all! 2 electrons just hanging around

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

.. + H : O : H H+1 .. Hydronium, H3O+ 2 pairs of nonbonding electrons zero electrons

Hydronium, H3O+ +1 H Both electrons are provided by the oxygen atom .. H : O : H ..

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

Diamond Structure

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