Concentration dependence of the structure of aqueous solutions of lutetium nitrate according to X-ray diffraction

Aqueous solutions of lutetium nitrate over a wide range of concentrations are studied by X-ray diffraction under standard temperature and pressure. The low-angle peaks in experimental scattering intensity curves are interpreted. It is shown that the structure of these solutions can be of two types. It is found that a saturated solution and solutions concentrated to a molar ratio of 1: 20 have a quasi-crystalline structure resulting from interionic interactions. It is determined that dilute solutions form a water-like structure characterized by a tetrahedral network of hydrogen bonds between the water molecules. It is found that low-angle peaks also appear in the intensity curves of dilute solutions; this proves that the so-called “long-range” order is preserved in these solutions. It is revealed that in all the studied systems, the contributions to the total scattering pattern that are responsible for the occurrence of pre-peaks are intercationic interactions.