Search

A mineral with the composition Pd(Bi0.53Sb0.47), intermediate between sobolevskite, ideally PdBi, and sudburyite, PdSb, from the Chineiskii Deposit (Transbaikal region, Russia), was studied by the SEM and XRD methods. Its crystal structure was solved and refined (R = 3.02%) based on single crystal X-ray diffraction data. The structure is orthorhombic, and the space group is Cmcm. The unit-cell parameters are a = 4.1465(4) Å, b = 7.1782(6) Å, c = 5.6843(4) Å, V = 169.19(2) Å3, Z = 2. The series of the structures β-PdBi–Pd(Bi0.53Sb0.47)–PdSb and sobolevskite–sudburyite are discussed. [ABSTRACT FROM AUTHOR]

The polytypic structure of Pd8T3 (T = As, Sb) compounds was revealed using the graph method. The topology of the layers and the regular sequence of their alternation are analyzed. The ordering of antimony and arsenic atoms by the positions at the nodes of layer-networks and the positional disorder in the sequence of alternating layers, which lead to the formation of different structural polytypes, are considered. [ABSTRACT FROM AUTHOR]

High-temperature transformation of β-PtBi2, a synthetic analogue of insizwaite, was studied under oxidizing conditions (on air). The behavior of the sample upon heating up to 660°C and cooling was studied by differential thermal analysis (DTA) and high-temperature X-ray powder diffraction. It was shown that polymorphic transitions of β-PtBi2 into high-temperature γ- and δ-polymorphs do not occur under thermal treatment in the oxidizing conditions (on air). The DTA curve shows two exothermic peaks at 318 and 620°C. The total weight change in the temperature range studied is +10.5%. No thermal reactions or weight changes were recorded upon cooling of the sample. According to the high-temperature diffraction experiment in situ, the decomposition of the synthesized phase into Pt and Bi was recorded with their subsequent oxidation to bismuth oxide Bi2O3 with the bismite-type structure and double platinum and bismuth oxide with the pyrochlore-type structure Bi2Pt2O7. The study by electron microprobe analysis showed that the grains of the transformed insizwaite are a finely dispersed mixture of two oxides. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23060065 [ABSTRACT FROM AUTHOR]