Reaction between and leads to the formation of a 3D diamond-like network (1). The structure is characterised by a network of intersecting channels of 3–4 \AA in diameter, filled with crystallisation water, most of which is released upon drying in air, causing the crystals to collapse. Analogous compound (2), based on paramagnetic , could only be obtained as a powder, due to the decomposition of the complex under slow diffusion conditions. It shows long-range magnetic ordering with nd magnetic hysteresis at 2 K. These properties are lost upon drying in air. After rehydration differently shaped hysteresis appears, which together with AC susceptibility measurements suggests the formation of a multiphase system. Subsequent dehydration–rehydration experiments show partial reversibility.