In this work, following our previous work on molybdate glasses, we employ a combination of neutron diffraction and neutron Compton scattering, augmented by ab initio harmonic lattice dynamics and Reverse Monte Carlo modelling to characterise the force-constant disorder in the tungsten oxide-based glasses. Specifically, we discuss the correlations between the average interatomic force constant magnitudes inferred from neutron Compton scattering and the glass formation ability, measured in terms of the value of the glass transition temperature, as well as the average bond-lengths and interatomic distances obtained from diffraction data analysis. Moreover, we provide a comparative analysis of the widths of force-constant distributions of individual atomic species in glasses and their precursor metal oxides based on the distributions of the widths of nuclear momentum distributions. Furthermore, we assess the degree of softening of atom-projected vibrational densities of states induced by the force-constant disorder in the glasses.

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Development of materials with novel composition to obtain rechargeable solid‐state batteries with improved capacity and energy density is one of the hot topics in material science. Inorganic and thermally stable oxyhalide materials are potential substitutes for the toxic and flammable organic liquid electrolytes used in the Li‐ion batteries. Herein, Li‐, Na‐, and K‐ion‐based oxyhalide materials doped with Ca, Ba, and Mg are synthesized. The samples are characterized by neutron and X‐ray diffractometry, Raman spectroscopy, thermal analysis, and transmission electron microscopy (TEM). Significant differences can be observed between the Li/Na/K‐series, but within the series the diffraction character of the compositions is similar; semi‐amorphous/crystalline phases are identified. Characteristic first‐ and second‐neighbor distributions reveal a very compact network structure. X‐ray diffractometry and Raman studies prove that the investigated Li‐, Na‐, and K‐based samples absorb water, even if they are kept under dry conditions. The Li3OCl antiperovskite phase is identified by X‐ray diffraction (XRD) in all the Ca‐, Ba‐, and Mg‐doped samples. TEM studies show that the morphology of the samples consists of nanograins of different size below 100 nm. According to elemental maps, the doping Ba forms oxide nanoparticles, while Mg is incorporated into the Na‐ and K‐based network structure.

Borosilicate glasses will be used to stabilize the high-level radioactive wastes for disposal in a geological repository. Understanding the effects of actinide addition to a borosilicate glass matrix is of great importance in view of waste immobilization. Lanthanides were considered as chemical surrogates for actinides. The local structures of Ce3+, Nd3+ and Eu3+ ions in borosilicate glass, have been investigated by synchrotron radiation based techniques. The atomic parameters, such as bond lengths and coordination environments derived from X-ray diffraction, in combined with Reverse Monte Carlo simulations show correlation with X-ray absorption fine structure data. The lanthanide ions are in the common network with the tetrahedral SiO4 and with the mixed trigonal BO3 and tetrahedral BO4 units. Second neighbor atomic pair correlations reveal that the Ce3+, Nd3+ and Eu3+ ions are accommodated in both Si and B sites, supporting that the lanthanide-ions are stabilized in the glass-matrix network. Microscopy and microanalysis provided information on the amorphous state and on the major elemental composition of the high lanthanide-concentration samples. The release of matrix components (Si, B, Na, Ba, Zr) is higher than that of lanthanides (Ce, Nd, Eu). Both types of elements show a decreasing release tendency with time.

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