The dimensionally stable alkaline solid block warewashing detergent uses an E-form binder forming a solid comprising a sodium carbonate source of alkalinity, a metal corrosion protecting alkali metal silicate composition, a sequestrant, a surfactant package and other optional material. The solid block is dimensionally stable and highly effective in removing soil from the surfaces of dishware in the institutional and industrial environment. The E-form hydrate comprises an organic phosphonate and a hydrated carbonate.