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We report the effect of compositional variation (Si/Al ratios of infinity, 11, 5, 3, 2, 1.4, and 1) on the vibrational properties of sodalite (framework code SOD), one of the simplest zeolite frameworks, through density functional theory (DFT) calculations. Additionally, we report the results of testing our DFT calculations on experimentally obtained infrared spectra of sodalites using different synthesis conditions to obtain spectra for sodalites with Si/Al = 1 and Si/Al → ∞ (siliceous sodalite). The experimental spectra are in good agreement with our DFT calculations in terms of predicting the characteristic vibrational modes of sodalites. However, we observe substantial peak broadening in the asymmetric stretching region and additional peaks in the experimental spectra that are not present in the calculated spectra. The second part of the study tests whether these additional peaks could arise from the existence of defects (i.e., hydroxyl groups and/or adsorbed water) in synthetic sodalite powders. The vibrational spectra in the high-frequency OH stretching region from DFT calculations are also compared to the experimental spectra. With the help of DFT calculations and prior studies, we conclude that the defects in siliceous sodalites are likely to be silanol (SiOH) groups. Although hydroxyl groups and adsorbed water are not the only defects that can occur in zeolitic materials, our DFT calculations suggest that their inclusion is able to account for many of the discrepancies between the experimental and simulated spectra.

A series of alkali metal rare-earth borates were prepared via hightemperature flux crystal growth, and their structures were characterized by single crystal X-ray diffraction (SXRD). Na 3 Ln(BO 3 ) 2 (Ln = La-Lu) crystallize in the monoclinic space group P2 1 /n, the potassium series K 3 Ln(BO 3 ) 2 (Ln = La-Tb) crystallize in the orthorhombic space group Pnma, while the Ln = Dy, Ho, Tm, Yb analogues crystallize in the orthorhombic space group Pnnm. To demonstrate the generality of this synthetic technique, high-entropy oxide (HEO) compositions K 3 N d 0 . 1 5 ( 1 ) E u 0 . 2 0 ( 1 ) G d 0 . 2 0 ( 1 ) D y 0 . 2 2 ( 1 ) H o 0 . 2 3 ( 1 ) ( B O 3 ) 2 a n d K 3 Nd 0.26(1) Eu 0.29(1) Ho 0.22(1) Tm 0.14(1) Yb 0.10(1) (BO 3 ) 2 were obtained in single crystal form. Radiation damage investigations determined that these borates have a high radiation damage tolerance. To assess whether trivalent actinide analogues of Na 3 Ln(BO 3 ) 2 and K 3 Ln(BO 3 ) 2 would be stable, density functional theory was used to calculate their enthalpies of formation, which are favorable.

A methodology to estimate the heat of mixing (Δ mix H ) for salt liquids in unexplored AkCl–AnCl x /LnCl x (Ak = alkali, An = actinide, Ln = lanthanide) systems is developed. It improves upon previous empirical approaches by eliminating the need for arbitrarily choosing the required composition at maximum short-range ordering, the minimum Δ mix H prior to performing the estimation, which avoids the intrinsic ambiguity of that approach. This semiempirical method has computationally reproduced the behavior of NaCl–UCl 3 and KCl–UCl 3 systems, providing Δ mix H values that agree well with the reported measurements within a propagated two standard deviations (2σ). The capability of the approach is demonstrated in its application to the entirety of the AkCl–UCl 3 and AkCl–PuCl 3 systems, the results from which have facilitated the accurate thermodynamic modeling of these and other AkCl–AnCl 3 /LnCl 3 systems. The resultant assessed Gibbs energy functions and models have been incorporated in the Molten Salt Thermal Properties Database–Thermochemical (MSTDB-TC).

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