Synthesis and properties of the NdSF compound, phase diagram of the NdF3–Nd2S3 system

Grigorchenko, V.M., Molokeev, M.S., Oreshonkov, A.S., (...), Elyshev, A.V., Andreev, O.V.// Journal of Solid State Chemistry//

https://doi.org/10.1016/j.jssc.2024.124640

The NdF₃–Nd₂S₃ system attracts attention of researchers due to the possibility of using LnSF compounds (Ln = rare earth element) as possible new p- and n-type materials. The samples of this system were synthesized from NdF₃ and Nd₂S₃. The NdSF compound belongs to the PbFCl structural type, P4/nmm space group, unit cell parameters: a = 3.9331(20) Å, c = 6.9081(38) Å. The experimentally determined direct and indirect NdSF bandgaps are equal to 2.68 eV and 2.24 eV. The electronic band structure was calculated via DFT simulation. The NdSF compound melts congruently at T = 1385 ± 10°С, ΔН_m = 40.5 ± 10 kJ/mol, ΔS = 24.4 ± 10 J/mol. The NdSF microhardness is 455 ± 10 HV. Five phase transformations in the NdF₃–Nd₂S₃ system were recorded by DSC; their balance equations were derived. The liquidus of the system calculated from the Redlich–Kister equation is fully consistent with the DSC data.