Very rapid quenching of liquids to form a glass, from which crystalline phases are subsequently obtained by devitrification, is a powerful technique for obtaining novel metastable compounds and crystal structures. By chilling aqueous solutions with liquid nitrogen we have synthesized new salt hydrates that contain a variety of different water polymer structures. What is striking about these polymers is that they are all based on pentagonal ring motifs, potentially providing important information about the structure of water in supercooled liquids. Our first goal in this experiment is to determine the structure of three novel hydrates produced by the quench method, MgSO4.9H2O and two compounds of MgSeO4 and MgMoO4 of as-yet uncertain hydration state. Our second goal is to measure the thermal expansion of MgSeO4.9H2O and relate that to the crystal's water dodecamer.