Over the last century, zeolites have come to be among one of the most widely used catalysts. With their unique framework and ion exchanging capabilities zeolites show great promise for future applications in solar cells, water purification and thermal energy storage. Zeolites are a group of aluminosilicates, where the aluminium atoms is the origin to many of these interesting properties. In order be able to exploit the full potential of zeolites, more insight of regarding the aluminium distribution in the framework is required. By utilizing computational methods such as cluster expansions and thermodynamic Monte Carlo sampling, this thesis has shed some new light on how it is energetically favourable for Al to cluster in protonated SSZ13. In addition, divalent counter ions was also examined and similar behaviour was found for them as well. These results prove that the generally accepted Löwenstein’s rule does not apply for charge compensated zeolites.