Probing Structural Changes in a Phosphonate-based Metal−Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal−organic frameworks (MOF): Z n2 . 5 ( H ) 0 . 4 − 0 . 5 ( C 6 H 3 O 9 P 3 ) ( H 2 O ) 1 . 9 − 2 ( N H 4 ) 0 . 5 − 0 . 6 a n d Zn 2.5(H)0.75(C6H3O9P3)(H2O)2(CH3NH3)0.25.