Synergetic Influence of Alkali-Metal and Lone-Pair Cations on Frameworks of Tellurites

Two Purely Inorganic Cationic Tellurite Materials Based on Group IB Metal Tetrafluoroborates with Similar Lamellar Cationic Layers: [Cu2F(Te2O5)](BF4) and [Ag18O2(Te4O9)4(Te3O8)(BF4)2]·2HBF4

Two new purely inorganic cationic tellurite networks of Group IB metal-based tetrafluoroborates, namely, [Cu₂F(Te₂O₅)](BF₄), 1, and [Ag₁₈O₂(Te₄O₉)₄(Te₃O₈)(BF₄)₂]·2HBF₄, 2, have been hydrothermally synthesized under mild conditions. The prepared materials have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and Raman spectroscopy, SEM-energy-dispersive spectroscopy, UV-vis-NIR diffuse reflectance, magnetic study, and TG analyses. Single-crystal diffraction studies show that both materials have similar cationic Cu/Ag tellurite layers with tetrafluoroborates as interlamellar charge-balancing anions. Magnetic results indicate that [Cu₂F(Te₂O₅)](BF₄), 1, exhibits a mainly short-range antiferromagnetic ordering within the 2D layer, and further detailed analysis of magnetic susceptibility analysis confirms a spin-singlet ground state with an energy gap of 85 K.

Lead Tellurite Crystals BaPbTe2O6 and PbVTeO5F with Large Nonlinear-/Linear-Optical Responses due to Active Lone Pairs and Distorted Octahedra

The exploration of nonlinear-/linear-optical crystal materials with high performance is an extremely difficult research project. Herein, the two new lead tellurite crystals BaPbTe₂O₆ and PbVTeO₅F were successfully obtained through a facile hydrothermal synthesis strategy. BaPbTe₂O₆ lies in the noncentrosymmetric (NCS) and chiral orthorhombic space group P2₁2₁2₁, featuring a unique _∞¹[PbTe₂O₆] chain consisting of the PbO₄ and TeO₃ building units, while PbVTeO₅F belonging to the centrosymmetric (CS) orthorhombic space group Pbca manifests a 2D layer made up of _∞¹[PbO₄F₂] chains and novel [V₂Te₂O₁₀F₂] clusters. Further, a systematic analysis of lead tellurites finds that the coordination geometries of the Pb atom exert a considerable influence on the connection modes of Pb-O and Te-O building units. BaPbTe₂O₆ shows a great second-harmonic-generation (SHG) effect of ∼5× the benchmark KH₂PO₄ (KDP) and a large optical birefringence of 0.086 at 590 ± 3 nm. PbVTeO₅F demonstrates a remarkably larger birefringence of 0.142 at 590 ± 3 nm, benefiting from the introduction of the VO₅F octahedral unit. Theoretical studies reveal that the large SHG and birefringence in BaPbTe₂O₆ can be attributed to TeO₃ and PbO₄ polyhedra with active lone pairs, while the remarkably enlarged birefringence in PbVTeO₅F is attributable to the highly distorted octahedral VO₅F. The functional orientations of active building units may offer a practical insight into the design of the desired optical functional materials.

Centrosymmetric Rb[Te2O4(OH)5] and noncentrosymmetric K2[Te3O8(OH)4]: metal tellurates with corner and edge-sharing (Te4O18)12- anion group

New nonlinear optical (NLO) crystals have become urgent need for extending laser wavelengths. By cation substitution between alkali metal (K+, Rb+), anion group arrangement transition were realized, and centrosymmetric Rb[Te2O4(OH)5]...

The crystal structure of KNa3Te8O18·5H2O exhibiting a ∞ 2[Te4O9]2− layer

KNa3Te8O18·5H2O, triclinic, P 1 ‾ $P\overline{1}$ (no. 2), a = 8.5701(4) Å, b = 8.7278(4) Å, c = 10.4082(5) Å, α = 67.582(2)°, β = 66.167(2)°, γ = 77.861(2)°, V = 656.85(6) Å3, Z = 1, R gt (F) = 0.0180, wR ref(F 2) = 0.0452, T = 296(2) K.

Hg3(Te3O8)(SO4): a new sulfate tellurite with a novel structure and large birefringence explored from d10 metal compounds

Our exploration of novel inorganic solids with large birefringence in the d10 Metal-Te4+-SO42- system afforded four new sulfate tellurites, Ga2(TeO3)(SO4)(OH)2, In2(TeO3)2(SO4)(H2O), Zn4(Te3O7)2(SO4)2(H2O) and Hg3(Te3O8)(SO4). Notably, Hg3(Te3O8)(SO4) exhibits the largest birefringence at 532 nm (0.184) and 1064 nm (0.166) among the reported metal sulfate tellurites.

Incorporating rare-earth cations with moderate electropositivity into iodates for the optimized second-order nonlinear optical performance

Introduction of rare-earth cations with moderate electropositivity into the iodate system afford three noncentrosymmetric rare-earth iodates RE_n(IO₃)_3n(H₂O) with optimized balance between SHG efficiency and optical band gaps.

Lone-pair self-containment in pyritohedron-shaped closed cavities: optimized hydrothermal synthesis, structure, magnetism and lattice thermal conductivity of Co15F2(TeO3)14

Co₁₅F₂(TeO₃)₁₄ features an extremely rare example of the Te(iv) lone pairs self-containment in pyritohedron-shaped [(TeO₃)₁₄]²⁸⁻ units, which allows Te atom to vibrate with large amplitude, leading to extremely low lattice thermal conductivity.

BaLiTe2O5X (X = Cl, Br): mixed alkali/alkaline-earth metal tellurite halides with [Te2O5]∞ chains

Isostructural BaLiTe₂O₅X (X = Cl, Br) feature [BaLiTe₂O₅]_∞ double layers, demonstrating wide optical bandgaps and large birefringence.

LiMII (IO3 )3 (MII =Zn and Cd): Two Promising Nonlinear Optical Crystals Derived from a Tunable Structure Model of α-LiIO3

Excellent nonlinear optical materials simultaneously meet the requirements of large SHG response, phase-matching capability, wide transparency windows, considerable energy band-gap, good thermal stability and structure stability. Herein, two new promising nonlinear optical (NLO) crystals LiM^II (IO₃ )₃ (M^II =Zn and Cd) are rationally designed by the aliovalent substitution strategy from the commercialized α-LiIO₃ with the perfect parallel alignment of IO₃ groups. Compared with parent α-LiIO₃ and related A^I ₂ M^IV (IO₃ )₆ , the title compounds exhibit more stable covalent 3D structure, and overcome the racemic twinning problem of A^I ₂ M^IV (IO₃ )₆ . More importantly, both compounds inherit NLO-favorable structure merits of α-LiIO₃ and show larger SHG response (≈14× and ≈12×KDP), shorter absorption edge (294 and 297 nm) with wider energy band-gap (4.21 and 4.18 eV), good thermal stability (460 and 430 °C), phase-matching behaviors, wider optical transparency window and good structure stability, achieving an excellent balance of NLO properties.

KBi(IO3)3(OH) and NaBi(IO3)4: from the centrosymmetric chain to a noncentrosymmetric double layer

Two bismuth iodates via tuning of alkali–metal ions reveal a structural transition from the centrosymmetric chain to a non-centrosymmetric double layer.