研究目的
Investigating the synthesis, structural characterization, physical properties, and theoretical studies of novel rare-earth metal-chalcogenides with unprecedented closed cavities.
研究成果
Five novel quaternary rare-earth chalcogenides, Cs2[RE8InS14] (RE = Ho–Lu), were synthesized, exhibiting a new structure type with large closed-cavities Cs4@S26. These compounds are paramagnets above 50K and have band gaps ranging from 2.45 to 2.72 eV. The study enriches host-guest chemistry and provides insights into the structural evolution with increasing G/H ratio.
研究不足
The study is limited to rare-earth elements from Ho to Lu. The magnetic properties were only tested above 50K for some compounds. The band gaps from theoretical calculations were smaller than the observed values, indicating a common underestimation in DFT calculations.
1：Experimental Design and Method Selection:
The compounds were synthesized using CsCl as both a Cs-source and a flux. A mixture of RE, In, and S with CsCl was sealed in quartz tubes and heated to 1273 K, held for 30 h, then cooled.
2：Sample Selection and Data Sources:
Stoichiometric mixtures of RE (Ho–Lu), In, and S were used.
3：List of Experimental Equipment and Materials:
Quartz tubes, programmable tube furnace, Rigaku Mercury CCD diffractometer for single-crystal data, Rigaku DMAX–2500 diffractometer for Powder XRD, Perkin-Elmer Lambda 950 UV-Vis spectrophotometer for diffuse reflectance spectra, Quantum Design PPMS-9T for magnetic properties.
4：Experimental Procedures and Operational Workflow:
The mixture was heated to 1273 K, held for 30 h, then cooled to 973 K at 3 K/h, to 573 K at 5 K/h, and naturally cooled.
5：Data Analysis Methods:
Crystal structures were analyzed by direct methods and refined using SHELX–2014 software. Band gaps were deduced from UV?Vis–NIR spectroscopy based on the Kubelka-Munk function.
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