CHE 104 Lecture Notes - Lecture 9: Silicon Carbide, Sodium Chloride, Lattice Energy
1 Feb 2017
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Document Summary
When you have more than one type of particle. Place one of the ions, usually the larger ion of the two, at the lattice points of a unit cell. Place the other ion in the holes of the lattice. Then fill the empty spaces in the lattice with the other atom. Usually the most common types are octahedral and tetrahedral holes. New rule: an atom on the edge counts as . 14 cl- atoms and 13 na+ atoms. The unit cell of silicon carbide is illustrated in your notes. The attraction between 2 oppositely charged ions is . These same relationships show up in the lattice energies of ionic compounds. It is the energy for the formation of one mole of a solid crystalline ionic compound when ions in the gas phase combine. This takes into account all of the ion-ion interactions. Start with separated ions in the gas state to form 1 mole of the compound in solid state.
