Experimental measurements and molecular simulations were used to describe the characteristics of the kaolinite/urea intercalation compound. The intercalation compound was synthesized by a mechanochemical method ant examined by X-ray diffraction and thermogravimetry. Additionally, a series of NpT(constant particle number-pressure-temperature) simulations was performed to identify thermodynamically stable basal spacings. From the simulations the most probable molecular orientations were determined for single and double layered arrangements of urea molecules Chat develop between the layers of kaolinite. (c) 2009 Elsevier Inc. All rights reserved.