Ln2Ga[B3O6(OH)]2[B7O9(OH)2](CH3CO2)2 (Ln = Y, Sm, Eu, Gd, Dy): A Series of Lanthanide Galloborates Decorated by Acetate Anions

YSO4F·H2O: A Deep-Ultraviolet Birefringent Rare-Earth Sulfate Fluoride with Enhanced Birefringence Induced by Fluorinated Y-Centered Polyhedra

Birefringent crystals can modulate and detect the polarization of light and are important optical functional materials. The birefringence is positively correlated to the anisotropy of the structure. By partially substituting sulfate anion with large electronegative fluorine in the parent compound Y2(SO4)3·8H2O, a new fluorinated rare-earth sulfate YSO4F·H2O with enhanced anisotropy was achieved. YSO4F·H2O features a dense 3D structure constructed by the polarizable [YOF] polyhedra and [SO4] tetrahedra. The diffuse reflectance spectrum reveals that it has a short UV absorption edge of below 200 nm. The substitution of the F- ion enhances the optical anisotropy, making the material exhibit an enhanced birefringence (0.0357 at 546 nm), which is 5.1 times that of the parent compound and is also larger than most deep-UV birefringent sulfates. It is expected that this work may shed useful insights in the exploration of deep-UV birefringent materials with enhanced optical performances..

BO3 Triangle and B@Zn2O3 Cationic Layer in the Structure of the Hybrid Zinc Acetate Borate [ZnAc]·[ZnBO3]

A zinc acetate borate, [ZnAc]·[ZnBO₃] (1), was synthesized under mild conditions; the B@Zn₂O₃ layer of 1 contains a 6-membered ring embedded with a rare BO₃ unit. The layers are pillared by acetate ions to form a 3D framework. The pillared structure of 1 supplies enough space as a nanoreactor, and the related application of CO₂-to-CO reduction has been confirmed.

Syntheses and structures of a new 2D layered borate and a novel 3D porous-layered aluminoborate

Two new layered and porous-layered borates ([H₂dap][B₇O₁₁(OH)] (1, dap = 1,2-propanediamine) and [H₃O]K_3.52Na_3.48{Al₂[B₇O₁₃(OH)][B₅O₁₀][B₃O₅]}[CO₃] (2)) have been solvothermally made. 1 features a 2D layer made of the [B₇O₁₃(OH)]^6- cluster, in which H₂dap is located in the windows of the layers. The fundamental building block (FBB) [B₇O₁₃(OH)]^6- cluster in 1 represents a new type of FBB of the hepta-borate family. 2 is a novel aluminoborate with a 3D porous-layered structure formed by three types of oxoboron clusters, [B₇O₁₃(OH)]^6-, [B₅O₁₀]^5- and [B₃O₇]^5-, respectively. The strict alternation of the different oxoboron clusters and AlO₄ tetrahedra leads to the abundant channel systems of the structure. 2 is the first aluminoborate (ABO) containing three types of oxoboron clusters and the first 3D porous-layered ABO with seven types of channels. UV-vis diffuse reflectance spectra reveal that both of them are wide band-gap semiconductors and have potential applications in UV regions.

Two novel 3D borates: porous-layer and layer-pillar frameworks

Two new borates, NaK_1.5[B{B₅O₉(OH)}{B₅O₈(OH)₂}_1/2] (1) and Na_3.5[Al{B₃O₆(OH)}{B₅O₁₀}_1/2{BO(OH)}] (2), have been made by a solvothermal method. Structure 1 is made of two types of oxoboron clusters ([B₅O₉(OH)]^4- and [B₅O₈(OH)₂]^3-) and BO₄ tetrahedra to form a 3D porous layer, in which the [B₅O₉(OH)]^4- clusters are bridged by BO₄ groups to produce a 2D B-O layer with 11-membered ring (MR) windows, while the [B₅O₈(OH)₂]^3- clusters as 2-connected pillars join the adjacent B-O layers to make a 3-D porous layer. Structure 2 is built from two types of oxoboron clusters ([B₃O₆(OH)]^4- and [B₅O₁₂]^9-), AlO₄ units and BO₂(OH) triangles to produce 3D pillar-layered aluminoborate (ABO), in which the [B₅O₁₂]^9- clusters are linked together to form a 2-D B-O layer; the [B₃O₆(OH)]^4- clusters and AlO₄ groups join each other to form 1D tubular ABO; and the BO₂(OH) triangles act as linkers to connect the adjacent B-O layer and the ABO tubes, resulting in 3D pillar-layered ABO. Interestingly, the ABO tubes decorated with the BO₂(OH) triangles act as pillars to make a 3D layer-pillared structure. UV-vis diffuse spectra indicate that both have cut-off edges below 190 nm, and the calculated band gaps are 5.75 and 5.78 eV, respectively.

Sr4Pb1.5Sb5O5Se8: a new mid-infrared nonlinear optical material with a moderate SHG response

The crystal structure and second-harmonic generation response of the new nonlinear optical material, Sr₄Pb_1.5Sb₅O₅Se₈, were examined.

RE(SO4)[B(OH)4](H2O), RE(SO4)[B(OH)4](H2O)2, and RE(SO4)[B(OH)4](H2O)·H2O: Rare-Earth Borate-Sulfates Featuring Three Types of Layered Structures

Using hydrothermal reactions, three series of rare-earth borate-sulfates, namely, RE(SO₄)[B(OH)₄](H₂O) (RE = La (1), Sm (2), Eu (3)), RE(SO₄)[B(OH)₄](H₂O)₂ (RE = Pr (4), Nd (5), Sm (6), Eu (7), Gd (8)), and RE(SO₄)[B(OH)₄](H₂O)·H₂O (RE = Tb (9), Dy (10), Ho (11), Er (12), Tm (13), Yb (14), Lu (15), Y (16)), have been synthesized, which represent the first rare-earth borate-sulfate mixed-anion compounds. All these compounds possess the same fundamental building anionic units of SO₄ and B(OH)₄ tetrahedra; however, they exhibit three different types of two-dimensional (2D) layered structures composed of 1D RE-B-O and RE-S-O chains. The rare-earth borate chains are similar in all compounds, while the rare-earth sulfate chains differ in each type of compound due to the various coordination modes of sulfate groups. On the basis of the measured UV-vis diffuse reflectance spectra, the optical band gaps of compounds 2, 3, 6, and 7 are estimated to be 4.66, 4.53, 4.62, and 4.50 eV, respectively. Luminescence studies show that compounds 2, 3, 6, and 7 exhibit strong emission in the orange or red regions. Furthermore, thermal analysis and magnetic susceptibility measurements for these four representative compounds have also been performed.

Four alkali metal molybdates with two types of Mo–O chains, ABMo3O10 (A = Li, B = Rb; A = Li, Na, K, B = Cs): synthesis, structure comparison and optical properties

The effects of cation size on the framework structures of four stoichiometrically equivalent alkali metal molybdates were discussed in detail.

Two tartratoborates with hybrid anionic groups from unusual condensation reactions

Two novel tartratoborates, namely, K₂[(C₄H₂O₆)(B₃O₄H)](H₂O) (1) and KCu₂[(C₄H₂O₆)₂B](H₂O)_2.5 (2), have been successfully synthesized by solvothermal reactions. They feature different kinds of structural types based on hybrid borate-tartrate motifs. The structure of compound 1 features a 3D network composed of novel [(C₄H₂O₆)₂(B₃O₄H)₂]^4- anionic groups interconnected by K⁺ cations. The [(C₄H₂O₆)₂(B₃O₄H)₂]^4- anion was formed by the condensation of two (B₃O₈H)^6- groups and two tartrate anions, and such condensation reaction has never been reported previously. Compound 2 exhibits a novel 3D network structure in which 2D {Cu₂[(C₄H₂O₆)₂B](H₂O)₂}^- layers are further interconnected via K⁺ ions. The [(C₄H₂O₆)₂B]^5- anion was formed by the condensation of two tartrate anions with a B(OH)₄^- unit. Magnetic measurements reveal a dominant antiferromagnetic interaction between neighboring Cu²⁺ ions in compound 2. Furthermore, UV-vis and infrared spectra and thermal analyses were also performed.

Two deep-ultraviolet nonlinear optical alkaline-earth metal borates based on different types of oxoboron clusters

Two non-centrosymmetric alkaline-earth metal borates were synthesized, showing the layered structures constructed from different oxoboron clusters and potentially new candidates for deep-UV NLO materials.