An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Twenty-seven new members of the A(2)Cu(2n)Ln(4)Q(7+n) (A = Cs, Rb; Ln = La-Nd, Sm, Gd-Yb; Q= S, Se) homologous series were synthesized in one of three structural types (indicated by n = 1, 2, 3). All the compounds contained 3D frameworks with alkali-metal-containing tunnels. For each increment in n, one Cu(2)Q was added, which was incorporated into the framework as an edge-sharing tetrahedron by replacing a square planar chalcogenide site. High-throughput DFT calculations predicted many of the phases to be thermodynamically stable. These predictions were compared with the synthesis results for the phases formed in each composition space. In the syntheses, heavier lanthanides showed a preference to start forming the n = 3 ACu(3)Ln(2)Q, which is consistent with the predictions. RbCuNd2Se4 and RbCuTb2Se4 were found to be thermally stable under vacuum at temperatures up to 1000 degrees C. Optical measurements revealed band gaps of 1.55(5) and 1.62(5) eV for CsCuCe2Se4 and RbCuTb2Se4, respectively, and a work function of 4.83(5) eV for CsCuPr2Se4. Additionally, some n = 3 ACu(3)Ln(2)Qs compounds exhibit a negative phonon mode because of a copper atom coordination, which may distort to a trigonal planar geometry at sufficiently low temperatures. The dynamic instabilities and the predicted distortion in the copper tetrahedra for the n = 3 ACu(3)Ln(2)Qs compounds were found to have a linear relationship with the atomic number of the lanthanides and the electronegativity of the lanthanides. The A(2)Cu(2n)Ln(4)Q(7+n) compounds can potentially find application as high-temperature thermoelectric materials and other semiconductors.

ACuZrQ(3) (A = Rb, Cs; Q = S, Se, Te) were synthesized as black platelet crystals. RbCuZrS3, RbCuZrSe3, and CsCuZrS3 crystallize in the KCuZrSe3 structure type with space group Cmcm, and RbCuZrTe3 and CsCuZrTe3 crystallize in the lower symmetry space group Pnma. The tellurides exhibit a second order Jahn-Teller distortion with off-centering of Zr in its octahedral environment. The magnitude of the distortion is larger in RbCuZrTe3 than in CsCuZrTe3. The structures of beta-CsCuS4 and Rb2Cu5Te5 were also determined. CsCuZrS3 melts at 910 C-circle and exhibits partial decomposition upon heating at 275 C-circle, while CsCuZrTe3 melts incongruently. Our DFT calculations of RbCuZrQ(3) (Q = S, Se) and CsCuZrS3 indicate direct gap semiconductors in agreement with experiments. ACuZrTe(3) (A = Rb, Cs) were calculated to be metals which was confirmed for RbCuZrTe3 with variable temperature conductivity measurements and consistent with heat capacity measurements. Spectroscopic measurements found a bandgap and work function of 1.44(5) eV and 4.89(5) eV for RbCuZrS3 and 0.95(5) eV and 4.67(5) eV for RbCuZrSe3, respectively. RbCuZrTe3 did not exhibit an optical bandgap and has a work function of 4.64(5) eV. RbCuZrTe3 exhibits a low thermal conductivity under 0.5 W m(-1) K-1 at room temperature.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.