Chemistry 1301A/B Lecture Notes - Lecture 19: Lattice Energy, Ionic Compound, Ionic Bonding

• School: Western University
• Department: Chemistry
• Course: Chemistry 1301A/B
• Professor: Felix Lee

Document Summary

Since ionic compounds do not form covalent bonds, but rather combine in ratios of positive and negative charge, their enthalpies are measured using either: experimental lattice enthalpies (born-haber cycles, or the theoretical lattice enthalpies. The lattice enthalpy (hat) is expressed as the enthalpy change associated with forming gaseous ions from one mole of a solid ionic crystal. It is always endothermic when expressed in this way. Born-haber cycle, which is a series of reactions that when summed (via hess". Law) represents the theoretical one-step reaction by which an ionic lattice is dissociated into its component gaseous ions (or vice versa), must be used as the enthalpy cannot be measured directly. + hia + hlatb + hib - hlat the goal is to solve this equation for hlat. Lattice enthalpies can also be determined purely theoretically, using the assumptions of the ionic model.