**7. Conclusions**

Mechanically initiated chemical reactions in solids are not new and presently there are many practical and theoretical achievements. Since mechanically initiated chemical reactions in solids have not received adequate attention yet, first of all a better understanding between researchers dealing with mechanochemistry and tribochemistry is needed. It was a major goal of this Chapter.

The new approach to mechanically initiated chemical reactions shows that the NIRAM-HSAB theory is important in accounting for most of very specific tribological findings and, also allows to account for the first mechanochemical reactions, for example

$$\text{HgS} + \text{Cu} \longrightarrow \text{Hg} + \text{CuS} \tag{2}$$

or modify the mechanism of heterogeneous C - C bond splitting in polymers.
