Liquid Ordering at the KDP {100}-Solution Interface
D. Kaminski, N. Radenovi, M. A. Deij, W. J. P. van Enckevort, and E. Vlieg
Cryst. Growth & Design 6 (2006) 588-591

Abstract:
We have determined the atomic structure of the KH2PO4 {100} interface in contact with solution for different pH values. Using X-ray diffraction data sets both the perpendicular and the lateral ordering in the solution have been determined. We find two ordered layers, of which only the first has lateral order. The atoms at the crystal surface show no relaxation, and the interface structure is the same for all pH values measured. The first liquid layer appears to be chemisorbed and compensates a broken hydrogen bond at the surface. This explains the fact that the {100} face is insensitive to the pH value.