Calcium malonate hydrate crystals were grown by the reaction method, with the aid of hydrosilica gel. Colourless and prismatic crystals up to 4.5 mm in size were obtained. Structural properties of the material were explored by employing X-ray diffraction (XRD), infrared (IR) absorption, laser Raman (LR), and thermogravimetric (TG) techniques. The IR spectrum indicates the presence of inequivalent water molecules in the structure of the compound. The thermal decomposition pattern of the sample suggests a three-stage decay scheme. About one-fifth of the weight is due to the presence of water of crystallization. The differential scanning calorimetric (DSC) study corroborates the presence of inequivalent water molecules in the structure. (C) 2004 Kluwer Academic Publishers.