There is a remarkable agreement between the condensation temperature (the temperature at which a solid or liquid of a given species forms) and the abundance of those elements vs. planetary location. For instance, if we group the compounds we observe based on the thermodynamic equilibrium condensation temperature, you would have the following temperature scale:
K Species
1600 Al, Ca oxides REFRACTORY
1200 Mg Silicates, Iron metal
1000 Feldspars
750 Iron sulfide
400 Magnetite
200 Water
150 Ammonia
100 Methane
70 Liquid nitrogen, other similar gases VOLATILE
With refractory being high temperature molecules, and volatile being low temp molecules.
Now if you use an adiabat (or a slight variation thereof) to decrease temperature with distance, you'll find that the chemical abundances in the planets correspond very well with the location of where a given temperature would be. This is especially true of the trace elements- if you look at the Martian meteorite trace element abundances, you'll see that the more volatile elements are in greater abundance. This is due to Mars' distance from the sun (1.52 AU as opposed to 1 AU). Likewise, the gaseous giants contain even more volatile compounds- Jupiter is rich in water, and may have formed due to the presence of the snow line, Saturn and Uranus have water and methane, Neptune is rich in Methane, Pluto and other Kuiper bodies have solid methane and N2 ice. You can add this to the list:
K Species
1600 Al, Ca oxides *Mercury
1200 Mg Silicates, Iron metal *Venus
1000 Feldspars *Earth
750 Iron sulfide *Mars
400 Magnetite *Asteroid Belt
200 Water *Jupiter, Saturn
150 Ammonia *Saturn, Uranus
100 Methane *Uranus, Neptune
70 Liquid nitrogen, other similar gases *Pluto, comets
Reference and general equilibrium calculations are described here, as is a temperature-radius profile: M.A. Pasek et al. 2005, Icarus, in press.