Solid-State Preparation, Structural Characterization, Physical Properties, and Theoretical Studies of a Series of Novel Rare-Earth Metal Chalcogenides with Unprecedented Closed-Cavities

Abstract

Multinary rare-earth metal chalcogenides have aroused great concern owing to their special structure characteristics and diverse physical functions. In this work, five novel rare-earth chalcogenides adopt the formula Cs2[RE8InS14] (where RE = Ho–Lu), obtained by the elemental mixture in CsCl flux at 1273 K. They are isotype and belong to orthorhombic Cmca (no. 64) [a = 15.711(7)–15.385(2) Å, b = 22.232(2)–21.786(2) Å, c = 15.483(5)–15.244(2) Å, V = 5408.4(4)–5130.1(7) Å3 and Z = 8], exhibiting a dense 3D [RE8InS14] framework consisting of RES6 octahedron and discrete InS4 tetrahedron. The large closed-cavities of Cs4@S26 are far apart and embedded within the network along bc-plane, which was discovered for the first time. The band gaps from 2.45 to 2.72 eV for Cs2[RE8InS14] were deduced from the UV–Vis–NIR spectroscopy based on the Kubelka–Munk function. A magnetic test indicates that the Cs2[RE8InS14] (RE = Ho–Yb) compounds possess paramagnetism above 50 K. In addition, the solid-state preparation, structural characterization, and theoretical studies together with a structure–G/H ratio relationship (G = atomic number of guest metals; H = atomic number of host metals) are also presented.

AZn4Ga5Se12 (A = K, Rb, or Cs): Infrared Nonlinear Optical Materials with Simultaneous Large Second Harmonic Generation Responses and High Laser-Induced Damage Thresholds

“…In combination with the previous work, we found that there are some interesting internal relationships between the structural dimensions and G/H ratio (G, guest metals; H, host metals) in the multinary chalcogenides. ,− For example, in the X/Zn/Ga/Q system, as the G/H value continues to decrease, it is possible to realize a transformation from a low-dimensional structure [e.g., one-dimensional Ba 8 Zn 4 Ga 2 S 15 (G/H = 1.33) or two-dimensional Na 6 Zn 3 Ga 2 S 9 (G/H = 1.20)] to a high-dimensional structure [e.g., 3D Ba 6 Zn 7 Ga 2 S 16 (G/H = 0.67)]. This strategy of achieving dimensional conversion through G/H ratio control guides us to seek new chalcogenides with different dimensions.…”

Rb2CuSb7S12: Quaternary Antimony-Rich Semiconductor Featuring a Three-Dimensional Open Framework and Exhibiting an Intriguing Photocurrent Response

“…So far, four types of structures are reported and given based on their different stoichiometries as follows: 1–1–2–4 type (i.e., RbCuSb 2 S 4 and CsCuSb 2 S 4 ), 1–2–1–3 type [i.e., ACu 2 SbS 3 (A = K, Rb, and Cs) and KCu 2 SbSe 3 ], 2–1–1–3 type (i.e., Na 2 CuSbS 3 and K 2 CuSbS 3 ), and 2–2–2–5 type (i.e., Rb 2 Cu 2 Sb 2 S 5 , Cs 2 Cu 2 Sb 2 S 5 , and Cs 2 Cu 2 Sb 2 Se 5 ). It is worth mentioning that the structure change trend of these compounds does not follow the previously reported inherent laws between the structural dimension and guest/host metal atom ratio. − For instance, RbCuSb 2 S 4 and KCu 2 SbS 3 show identical A/(Cu + Sb) ratios (i.e., 0.33), but the former possesses a 3D framework structure and the latter adopts a 2D-layered structure. Further structural analysis shows that the Cu/Sb ratio is the major determinant of structural dimension change (shown below).…”

A unique [Sb6O2S13]12−finite chain in oxychalcogenide Ba6Sb6O2S13leading to ultra-low thermal conductivity and giant birefringence

“…Usually, low-dimensional chalcogenides can be obtained by enhancing the proportion of charge-balanced cations according to the viewpoint of “dimensional reduction”. 18 Actually, this structural law is not followed in this quaternary family, for instance, Ba 2 Sb 2 O 2 S 3 , Sr 2 Sb 2 O 2 Se 3 , and Sr 3.5 Pb 2.5 Sb 6 O 5 Se 10 , have the same [X/Sb] ratio of 1.0, but their corresponding structural dimensions are 0D, 1D, and 2D, respectively. Similar phenomena can also be observed in other SCALP-based chalcogenide systems.…”