The crystal structure of TlMgCl₃ from 290 K to 725 K

Abstract

The title compound, thallium magnesium trichloride, has been identified as a scintillator with both moderate gamma-stopping power and moderate light yield. Knowledge of its crystal structure is needed for further development. This work determines the crystal structure of TlMgCl3 to be hexagonal P63/mmc (No. 194) and isostructural with RbMgCl3, contrary to previously reported data. This structure was obtained by single-crystal X-ray diffraction and was further confirmed by neutron diffraction measurements. Extending neutron diffraction measurements to high temperature, the data show that TlMgCl3 maintains this crystal structure from 290 K up through 725 K, approaching the melting point of 770 K. Anisotropic thermal expansion coefficients increase over this temperature range, from 31 to 38 × 10−6 K−1 along the a axis and from 19 to 34 × 10−6 K−1 along the c axis.

Structures and Ionic Transport Properties of Perovskite-Related BIAIIX3 and BIA2IIX5 Halides

“…A better way to do so is using structure field diagrams in which the stability of perovskites and related structures are mapped according to their ionic radii quotients. This was already done by Beck et al and Schilling and Meyer, who gave a comprehensive overview of several ABX 3 − and A I B 2 II X 5 / B I A 2 II X 5 ,,,,− halides and showed the correlation of the different structure types with the ratio of the ionic radii quotients r ( A )/ r ( X ) and r ( B )/ r ( X ), as depicte...…”

High-entropy alloy screening for halide perovskites

“…Throughout the literature, the boundary between what is considered perovskite and not considered perovskite is ambiguous. 1,2 We limit our search to the 282 inorganic and 40 organic ABX 3 compounds that have been experimentally observed and previously labeled as “perovskites” (Tables S10 18–20,27,111,112,115,123,179,306–539 and S11 (ESI†), 315,466,524,526,540–558 respectively). We exclude the 90 inorganic HP that have been proposed but not synthesized (Table S12, ESI†).…”