Conclusion

In the main part of this book it has been shown that the silicates, more than any other group of chemical compounds with the exception of the organic carbon compounds, exhibit an enormous chemical and structural variability. In order to demonstrate this variability, a large number of silicates with different structures were described. Using these silicates as examples, it has been shown that the atomic structure of a silicate is controlled mainly by its chemical composition and to a lesser extent, by temperature and pressure. To obtain a better understanding of the large number of observed silicates, a classification has been described and used which is based on crystal chemical principles and, therefore, reflects structural relations between the silicates.