GEOL 2081 Study Guide - Bond Energy, Linus Pauling, Ion
Document Summary
Building mineral structures: crystals reflect orderly internal arrangement of ions/atoms. Structure of crystalline materials necessary to understand properties: ions behave as spheres (ionic and metallic bonding, how variably sized spheres (ions) are arranged determine crystalline. Based on size and charge: spheres pack together in a crystal structure to minimize void space. If spheres are same size, two packing schemes result, called closest packing: creating 2 void spaces pointing up or down, hexagonal closest packing (hcp, void b and c respectively. Each sphere touches 6 others in layers (a: as close as possible, creates 2 void spaces (b and c) Next layer, added over voids (b) b layer. Thus creating ababab sequence: cubic closest packing. 6 in plane, 3 above, 3 below: said to coordinate . 3rd layer on top of b in dimples that over lie c voids: 12 fold coordination. Result in packing (coordination) of different sized spheres: cations and anions bond, forms crystal structure.
