Solid State Physics

Chapter 3

Crystal Binding

3.1 INTRODUCTION

Different criteria have been applied to classify materials. One criterion is the state of aggregation, according to which substances have been divided into three main classes: solid, liquid, and gas; the other criterion is the geometry or symmetry properties of the molecules or crystals, according to which substances have been divided into 32 point groups (classes) and 230 space groups. According to the criterion of the types of bonding that we are discussing here, substances have been divided into the following types: (1) ionic, (2) covalent, (3) metallic, (4) molecular or Van der Waals, and (5) hydrogen bond. In any substance, the binding may not be purely of one type, but different types may be present ...