A novel hydrate of alpha-cyclodextrin crystallised under high-pressure conditions

The technique of high-pressure crystallisation from solution has been applied to the study of alpha-cyclodextrin hydrate formation. A previously unobserved hydrate, here termed Ib, has been obtained at 0.65 GPa and characterised by single-crystal X-ray diffraction using synchrotron radiation. This form exhibits a combination of structural features of other known hydrates and hydration states obtained by theoretical calculations but never found experimentally before.