# Introduction

You have looked at the structural formulas of a number of molecules so far in this course.

For example, Figure 1 is a structural formula for hexan-1-ol, which shows you the immediate neighbours of any particular atom. It is a simply a two-dimensional drawing. But in studying the structures obtained by the technique of X-ray crystallography, it can be shown that the atoms in a substance have a definite three-dimensional arrangement in space.

CH3—CH2—CH2—CH2—CH2—CH2—OH

Figure 1 The structural formula for hexan-1-ol

An understanding of the shapes of molecules is often the key to an understanding of chemical reactions, and this is the main focus of your study in this session.

OpenLearn - Discovering chemistry
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