Model of short-range order in a concentrated lanthanum trichloride aqueous solution from x-ray diffraction studies

Abstract

A concentrated aqueous solution of LaCl 3 has been investigated by the X-ray diffraction method. The main features of the pair function are consistent with the presence of the [La(H 2 O) 9 Cl 2 ] + complex, additionally hydrated in the second sphere. The outer-sphere Cl - ions are hydrogen bonded to the inner-sphere water molecules. The La 3+ -Cl - distance points either to a trigonal orientation of inner-sphere water molecules and the hydrogen bond angle of 110 o or to the tilt angle of 30 o and a linear hydrogen bond