Neutron diffraction study on the hydration structure of carbonate ion by means of 12C/13C isotopic substitution method

Time-of-flight (TOF) neutron diffraction measurements were carried out for C-12/C-13 isotopically substituted aqueous 10 mol% K2CO3 solutions in D2O in order to obtain structural information on the hydration structure of CO32-. Structural parameters concerning water molecules in the first hydration shell of CO32- were determined through the least-squares fitting analysis of the observed intermolecular difference function, Delta(inter)(C)(Q). It has been revealed that the first hydration shell of CO32- consists of 9.1(5) water molecules with the intermolecular C(CO32-)center dot center dot center dot D-WI(D2O) distance of 2.68(1)angstrom. (c) 2006 Elsevier B.V. All rights reserved.