[Encyclios]

More complex solid solutions: aliovalent substitution

Considering solid solutions in a more general perspective, we can distinguish them into two broad classes: those obtained by homovalent substitutions and those obtained by heterovalent or aliovalent substitutions.

In the first case the ions are replaced by others with the same charge (as in the examples seen so far), while in the second case the ions are replaced by others of different charge. Consequently, in this case, other changes are required to achieve electrical neutrality, either by an ionic mechanism of the “vacancy or interstitial” type (ionic compensation), or by an electronic mechanism of “electrons or holes” (electronic compensation).