Zeolites are microporous aluminosilicate minerals which are characterised by their highly crystalline framework structures. Having distinct porosity, zeolites are used in a variety of applications including hydrocracking, catalysis, molecular sieving and as drug release materials. The synthesis of novel ‘designer zeolites’ for specific applications is one of the primary motivations in zeolite research, being listed as one of the top ten breakthroughs in 2011 by Science. Simulations have predicted millions of new conceivable hypothetical zeolite structures, however there is no guidance as to which are synthetically feasible. This problem can be solved by considering the compressive properties of zeolite frameworks known as ‘the flexibility window’,2 which is an integral parameter in deeming synthetic viability.