Structural evolution of the amorphous solids produced by heating crystalline MgHPO₄ · 3H₂O

The precise structural characteristics of the amorphous solids that are generated during the dehydration of crystalline MgHPO₄ · 3H₂O (newberyite) are reported. The results show that a dramatic change in the distribution of phosphate anions (i.e., chains of corner-linked PO₄ tetrahedra) occurs during the process of dehydration and that anions up to 13 PO₄ tetrahedra in length are formed. The distribution of phosphate anions formed at intermediate stages of the dehydration process was found to be in quantitative agreement with the theory of Parks and Van Wazer.