 It has been known since 1926 that hexoses in the crystalline solid state assume the cyclic form.The "α" and "β" forms, which are not enantiomers, will usually crystallize separately as distinct species.For example, -glucose forms an α crystal that has specific rotation of +112° and melting point of 146 °C, as well as a β crystal that has specific rotation of +19° and melting point of 150 °C.