Na2B6O9F2: A Fluoroborate with Short Cutoff Edge and Deep-Ultraviolet Birefringent Property Prepared by an Open High-Temperature Solution Method

Sb2O2SeO3 and Sb2O(SeO3)2: Two-Layered Antimony(III) Selenites with Enhanced Birefringence

Two antimony selenites, Sb2O2SeO3 and Sb2O(SeO3)2, were synthesized by simultaneously incorporating stereochemically active lone pair electrons containing SeO32- and Sb3+. These compounds are structured with [SbOx] polyhedra and [SeO3] units within a two-dimensional framework. Both of them exhibit cutoffs at 300 and 330 nm within the ultraviolet (UV) range and demonstrate significant birefringence, with indices of 0.069 and 0.126 at 546 nm, respectively. These properties highlight their potential as UV birefringent materials. Structural analyses and theoretical calculations reveal that their exceptional birefringence results from the synergistic interactions between SeO32- anions and Sb3+ cations.

NaRbB10O14(OH)4 and Na3CsB10O16(OH)2: Two Cases of Hydroxyborates with [B5Om(OH)n] Units and Deep Ultraviolet Cutoff Edges

Two deep ultraviolet (DUV) hydroxylated-alkali-metal borates, NaRbB10O14(OH)4 (I) and Na3CsB10O16(OH)2 (II), have been successfully synthesized by a high-temperature solution and solvothermal method. Both of them feature [B5Om(OH)n] units, which form chains for (I) and bilayers with nine-membered boron rings for (II). It is worth noting that both compounds exhibit very wide theoretical band gaps of 7.33 and 6.55 eV for (I) and (II), respectively, which denotes that they should have desirable DUV transmittance ability. Moreover, the title compounds have moderate birefringence owing to the π-conjugated [BO3], [BO2(OH)] groups, corresponding to 0.070 for (I) and 0.054 for (II) at 1064 nm. The structure characteristics and optical properties were also investigated and discussed. The results make it beneficial for exploring novel DUV hydroxylated borate optical crystals.

New antimony fluorooxoborates with strong birefringence and unprecedented structural characterisation

Fluorooxoborates constitute a rich source of optical crystals due to their structural diversity and excellent performance. Antimony fluorooxoborates with stereochemically active lone pairs of electrons still have not been found, although the first antimony borate was discovered several years ago. In this study, we have achieved the successful synthesis of the first antimony(III) fluorooxoborate with an unprecedented [B2O4F]∞ chain, namely SbB2O4F. Remarkably, SbB2O4F shows strong birefringence (0.171@1064 nm) and short UV cutoff edges (about 220 nm) according to calculations. The birefringence of SbB2O4F mainly originates from the highly distorted [SbO4] groups.

PbTeB4O9: a lead tellurium borate with unprecedented fundamental building block [B4O10] and large birefringence

Herein, the first lead tellurium borate, PbTeB4O9, with an unprecedented fundamental building block [B4O10] was successfully synthesized. The near-parallel alignment of [B4O10] groups and [TeO3] polyhedra resulted in a high birefringence (0.099@1064 nm). The structure-property relationship was discussed by using the first-principles calculations.

Optically Anisotropic Mixed-Metal Fluoroiodate Ba2[GaF5(IO3F)] with a Wide Optical Transparent Window and a Moderate Birefringence

An optically anisotropic alkali-earth-metal gallium fluoroiodate, Ba2[GaF5(IO3F)] (1), was ingeniously obtained by integrating fluoride and fluoroiodate functional units under moderate hydrothermal conditions. It features a three-dimensional (3D) structure constructed by the highly polarizable fluoroiodate unit [IO3F] and the fluoride groups [GaOF5] and [BaO3Fx] (x = 6, 7). The compound is stable at temperatures up to 500 °C. With the synergistic interaction between [IO3F] and the fluoride groups, the mixed-metal fluoroiodate induces a short ultraviolet cutoff edge at about 230 nm, a medium measured birefringence of 0.068 @ 550 nm, and a wide optical transparent window (0.34-11.9 μm), indicating that 1 has potential applications as a birefringent material from near-UV to mid-infrared. Theoretical calculations prove that the optical characteristics of the compound are mainly attributed to [IO3F] and the fluoride functional groups. This work demonstrates that the presence of various specific functional groups in compounds will help to develop promising inorganic functional materials possessing good optical performance.

Ba3.75MgB7O14F2.5: A Mixed Alkaline-Earth Metal Borate Fluoride with Short Ultraviolet Cutoff Edge and Large Birefringence

Fluorine-containing borate crystal materials are particularly attractive due to their rich structural chemistry and excellent properties for optical applications. In this work, a new compound Ba3.75MgB7O14F2.5 has been synthesized through the high-temperature solution method. In the crystal structure of Ba3.75MgB7O14F2.5, the [B7O14] basic building unit and the [MgO3F3] octahedra are interconnected to create a complex three-dimensional network. The structural feature of the less commonly observed [B7O14] units is discussed, and it has been found that such units in Ba3.75MgB7O14F2.5 are most conducive to achieving large birefringence. In addition, Ba3.75MgB7O14F2.5 exhibits good thermal stability, a short ultraviolet cutoff of 203 nm, and large birefringence (0.081@546 nm), indicating its potential as a new UV birefringent crystal.

Three Polyborates with High-Symmetry [B12O24] Units Featuring Different Dimensions of Anion Groups

Three polyborates, namely, LiNa₁₁B₂₈O₄₈, Li_1.45Na_7.55B₂₁O₃₆, and Li₂Na₄Ca₇Sr₂B₁₃O₂₇F₉, were synthesized via the high-temperature solution method. All of them feature high-symmetry [B₁₂O₂₄] units, yet their anion groups exhibit distinct dimensions. LiNa₁₁B₂₈O₄₈ features a three-dimensional anionic structure of ³[B₂₈O₄₈]_∞ framework, which is composed of three units: [B₁₂O₂₄], [B₁₅O₃₀], and [BO₃]. Li_1.45Na_7.55B₂₁O₃₆ possesses a one-dimensional anionic structure of ¹[B₂₁O₃₆]_∞ chain consisting of [B₁₂O₂₄] and [B₉O₁₈] units. The anionic structure of Li₂Na₄Ca₇Sr₂B₁₃O₂₇F₉ is composed of two zero-dimensional isolated units, namely, [B₁₂O₂₄] and [BO₃]. The novel FBBs [B₁₅O₃₀] and [B₂₁O₃₉] are present in LiNa₁₁B₂₈O₄₈ and Li_1.45Na_7.55B₂₁O₃₆, respectively. The anionic groups in these compounds exhibit a high degree of polymerization, thereby augmenting the structural diversity of borates. And the crystal structure, synthesis, thermal stability, and optical properties were meticulously discussed to guide the synthesis and characterization of novel polyborates.

Na2BaB12O18F4: A Mixed Alkali/Alkaline-Earth Metal Fluorooxoborate with Two Unprecedented Interpenetrating Three-Dimensional B-O/F Anionic Networks and a Short Ultraviolet Cutoff Edge

Fluorooxoborates are promising yet largely untapped crystal materials for linear and nonlinear optical applications. The introduction of a strong electronegative F atom into an oxyboron anionic group offers a virtually unlimited chance for structural engineering and ultimately purposeful tuning of the macroscopic optical properties of the crystal. Herein, a new mixed alkali/alkaline-earth fluorooxoborate, Na₂BaB₁₂O₁₈F₄, was synthesized in a closed system. Na₂BaB₁₂O₁₈F₄ features a [B₆O₁₁F₂] fundamental building unit (FBB), which polymerizes into two new (first example) independent interpenetrating three-dimensional (3D) B-O/F anionic networks constructed entirely from BO₃ and BO₃F units. Based on optical characterizations and the first-principles calculations, Na₂BaB₁₂O₁₈F₄ exhibits a moderate birefringence (0.054 @ 1064 nm) and a short ultraviolet (UV) cutoff edge (below 190 nm). The successful synthesis and characterization of Na₂BaB₁₂O₁₈F₄ may speed up the subsequent discovery of other mixed alkali/alkaline-earth metal fluorooxoborates.

Li3B8O13X (X = Cl and Br): Two New Noncentrosymmetric Crystals with Large Birefringence Induced by BO3 Units

Enthusiasm for the exploration of nonlinear alkali metal borates remains high. Focusing on the Li-B-O-X (X = Cl and Br) system, two examples of noncentrosymmetric borates, Li₃B₈O₁₃Cl and Li₃B₈O₁₃Br, were obtained using a high-temperature solution method under vacuum conditions. Structurally, the Li₃B₈O₁₃X crystals exhibit two independent alternately arranged three-dimensional B-O network structures formed by the basic building block unit B₈O₁₆. The performance measurements demonstrate their short ultraviolet cutoff edges. The theoretical calculation indicates that the BO₃ units dominate the contribution to their large optical anisotropy with the birefringence, 0.094 and 0.088@1064 nm for Li₃B₈O₁₃Cl and Li₃B₈O₁₃Br, respectively.

BaB2P2O8F2: A Fluoroborophosphate with [B2P2O8F2]∞ Layers and Deep-Ultraviolet Cutoff Edge

A fluoroborophosphate, BaB₂P₂O₈F₂, was successfully obtained. Its structure contains a novel [B₂P₂O₈F₂]_∞ layer containing six-membered rings, which is formed by the fundamental building block composed of three types of non-π-conjugated groups, [PO₄], [BO₄], and [BO₂F₂]. BaB₂P₂O₈F₂ has a deep-ultraviolet (DUV) cutoff edge (λ < 200 nm) and a tiny birefringence (Δn = 0.007 at 532 nm), which originates from the constituent non-π-conjugated groups. The title compound enriches the versatility of the fluoroborophosphates, encouraging further research into DUV materials in fluoroborophosphate systems.

CsB3O4(OH)2: a new deep-ultraviolet birefringent crystal with [B3O4(OH)2] anionic group

A new cesium hydroxyborate CsB₃O₄(OH)₂, was designed and synthesized by a hydrothermal method. Remarkably, CsB₃O₄(OH)₂ presents novel [B₃O₄(OH)₂]_∞ chains formed by [B₃O₄(OH)₂] fundamental building blocks (FBBs). The report of less common [B₃O₄(OH)₂] FBBs and [B₃O₄(OH)₂]_∞ chains in CsB₃O₄(OH)₂ enriches the structural diversity of hydroxyborates. In addition, CsB₃O₄(OH)₂ has a wide transparent window in the DUV spectral range and a large birefringence.

NaB3O4F(OH): A Hydroxyfluorooxoborate with One-Dimensional Chain Featuring Large Birefringence and Short Ultraviolet Cutoff Edge

A new sodium hydroxyfluorooxoborate, NaB₃O₄F(OH) (NBOFH), was discovered and synthesized. NBOFH features the unprecedented [B₃O₄F(OH)] infinite chain constructed by the novel fundamental building block (FBB) of [B₃O₅F(OH)]. NBOFH has a large birefringence of 0.097 at 1064 nm and short ultraviolet (UV) cutoff edge below 200 nm. First-principles calculations and response electron distribution anisotropy (REDA) were performed to explain the structure-property relationships. This work provides a novel strategy for the synthesis of deep-ultraviolet birefringent crystals and enriches the structural diversity of the emerging hydroxyfluorooxoborates.

An excellent deep-ultraviolet birefringent material based on [BO2]∞ infinite chains

Birefringent materials play indispensable roles in modulating the polarization of light and are vital in the laser science and technology. Currently, the design of birefringent materials operating in the deep-ultraviolet region (DUV, λ ≤200 nm) is still a great challenge. In this work, we developed a new DUV birefringent crystal LiBO₂ based on [BO₂]^∞ infinite chains in the Li-B-O system, which simultaneously achieves the shortest UV cutoff edge (164 nm) and the largest birefringence (≥0.168 at 266 nm) among all the reported borate-based DUV birefringent materials. Single crystals of LiBO₂ with dimensions up to Ø55 × 34 mm³ were grown by the Czochralski method, providing access to large-sized single crystal with low cost. Moreover, it has a high laser damage threshold and stable physicochemical properties. These outstanding characters unambiguously support that LiBO₂ can be an excellent birefringent material for DUV application.

NaBa3[M2B7O16(OH)2]F2 (M = Ge, Si): Two Synthetic F Analogues of Garrelsite with [B7O16(OH)2]13- Polyanions and Deep-Ultraviolet Cutoff Edges

Two new borogermanate/borosilicate fluorides, namely, NaBa₃[M₂B₇O₁₆(OH)₂]F₂ (M = Ge, Si), have been successfully synthesized through a conventional mild hydrothermal method. They represent the first examples of mixed alkali and alkaline-earth borogermanate/borosilicate fluorides. NaBa₃[M₂B₇O₁₆(OH)₂]F₂ (M = Ge, Si) crystallize in the space group of C2/c, and their structures feature a unique 3D anionic framework composed of [B₇O₁₆(OH)₂]^13- polyanions corner-sharing with SiO₄ or GeO₄ tetrahedra, forming 1D 10-membered-ring tunnels along the b axis, which are filled by Na⁺, Ba²⁺, and F^- ions. UV-vis-near-IR absorption spectra identify the title compounds possessing short deep-ultraviolet absorption edges (below 200 nm), while their birefringences were calculated to be 0.021 and 0.016 at 1064 nm, respectively. Optical property, thermal stability, and theoretical calculations have also been conducted on NaBa₃[M₂B₇O₁₆(OH)₂]F₂ (M = Ge, Si).

MM'B3O4F3 (M = K; M' = Na, K, Cs): Alkali-Metal Fluorooxoborates with ∞1[B3O4F3] Chains and Deep-Ultraviolet Cutoff Edges

Three mixed-alkali-metal fluorooxoborates, KNaB₃O₄F₃ (I), K₂B₃O₄F₃ (II), and KCsB₃O₄F₃ (III), were acquired in a closed system. I-III are isomorphic and adopt orthorhombic structures [Pbcn (No. 60)] with wavy parallelly arranged pseudolayers composed of _∞¹[B₃O₄F₃] chains, which exhibit slight differences in the arrangement modes of the fundamental building blocks. First-principles calculations illustrate that they all have moderate birefringence and large band gaps on the order of 7.0 eV, suggesting deep-ultraviolet (DUV) cutoff edges. In order to investigate the main source of the optical properties, the electronic structure and anisotropy of the response electron distribution were analyzed. Experimental characterizations for I confirm the structure and DUV transparence ability.

Ba2B5O8(OH)2(NO3)·3H2O: the design of an alkaline earth metal borate-nitrate optimized from a hydroxylic borate

The first alkaline earth metal borate-nitrate, namely Ba₂B₅O₈(OH)₂(NO₃)·3H₂O (BBNOH), has been synthesized by the hydrothermal method. BBNOH crystallizes in the space group of P2₁/c and shows two-dimensional (2D) ²_∞[B₅O₈(OH)₂]^3- borate anion layers, and the hydrated barium cations and the [NO₃]^- anions are located between the layers. The process of optimizing the structure of Ba₂B₅O₈(OH)₂OH to BBNOH has been discussed. The first principles calculation has been used to calculate the birefringence of Ba₂B₅O₈(OH)₂(NO₃)·3H₂O, and the value is 0.033@1064 nm, which is mainly originated from the borate anions and the π conjugated [NO₃]^- anions.

Pb2Al2B3O8F3: Structure and Properties of a New Fluoroaluminoborate with Non-traditional Chain-like B3O8 Group

A new fluoroaluminoborate, Pb2Al2B3O8F3, with a non-traditional chain [B3O8]7- was synthesized by high temperature reactions in closed systems for the first time. Different from the traditional [B3O8]7- ring [(3:Δ +...

A2B6O9F2 (A = NH4, K): new members of A2B6O9F2 family with deep-UV cutoff edges and moderate birefringence

Two new fluorooxoborates A2B6O9F2 (A = NH4, K) with different two-dimensional [B6O9F2]∞ layered structure constructed by the fundamental building block [B6O11F2] were obtained.

NaRbB3 O4 F3 : A New Fluorooxoborate with a Short UV Cutoff Edge Enriching the Structural Chemistry of Borate

The combination of RbB₃ O₄ F₂ and NaF generates a new member of fluorooxoborates, NaRbB₃ O₄ F₃ , with a wide transparency range from the IR to DUV region. NaRbB₃ O₄ F₃ shows a three-dimensional (3D) structure composed of 1D [B₃ O₄ F₃ ]_∞ chains, [NaO₃ F₃ ] and [RbO₅ F₅ ] polyhedra. The structural evolution from NaRbB₃ O₄ F₃ to RbB₃ O₄ F₂ , as well as the structural comparison between NaRbB₃ O₄ F₃ and its identical stoichiometry compound, Li₂ B₃ O₄ F₃ were discussed in detail. The IR spectrum verifies its structural validity. The spectral measurement shows that the reflectance has no obvious change in the range of 175-300 nm, and its cutoff edge is below 175 nm. In addition, theoretical calculations are carried out to understand its electronic structure and optical properties.

Fluorine-Driven Enhancement of Birefringence in the Fluorooxosulfate: A Deep Evaluation from a Joint Experimental and Computational Study

Understanding and exploring the functional modules (FMs) consisting of local atomic groups can promote the development of the materials with functional performances. Oxygen-containing tetrahedral modules are popular in deep-ultraviolet (DUV) optical materials, but their weak optical anisotropy is adverse to birefringence. Here, the fluorooxosulfate group is proved as a new birefringence-enhanced FM for the first time. The birefringence of fluorooxosulfates can be 4.8-15.5 times that of sulfates with the same metal cations while maintaining a DUV band gap. The polarizing microscope measurement confirms the birefringence enhancement by using the millimeter crystals experimentally. The theoretical studies from micro and macro levels further reveal a novel universal strategy that the fluorine induced anisotropic electronic distribution in fluorooxo-tetrahedral group is responsible for the enhancement of birefringence. This study will guide the future discovery of DUV optical materials with enlarged birefringence.

Na2La2B10O19: a new lanthanum sodium borate with infinite 2D layer 2∞[B10O19]8− and moderate birefringence

A new La-based borate Na₂La₂B₁₀O₁₉ with infinite 2D double layers composed of (B₅O₁₂)⁹⁻ FBBs and a moderate birefringence of 0.06 at 1064 nm.

Ba2B7O12F with novel FBB [B7O16F] and deep-ultraviolet cut-off edge

A new fluorooxoborate Ba₂B₇O₁₂F features novel FBB [B₇O₁₆F] and two different sizes of channels in its anionic structure, which possesses a deep-ultraviolet cutoff edge of 180 nm and a large bandgap of 6.67 eV.

Synthesis, crystal structure and theoretical calculations of two rare-earth borates with DUV cut-off edges

Two isomorphic rare-earth borate crystals, YZnB₅O₁₀ and GdZnB₅O₁₀, show three-dimensional structures constructed from two-dimensional {[B₅O₁₀]⁵⁻}_n layers with the Y or Gd, and zinc ions filled in the interlayers, and exhibit DUV cut-off edges (<190 nm).

NaKB6O9F2: a new complex alkali metal fluorooxoborate with puckered layers

Introducing F atoms into the 3D borate framework is beneficial to synthesize layered fluorooxoborates, which ensures moderate birefringence.

RbB3O4F2: a rubidium fluorooxoborate with an unprecedented [B3O5F2]3- functionalized unit and a large birefringence

A new rubidium fluorooxoborate, RbB₃O₄F₂, was structurally designed and synthesized by using the strategy of fluorine-introduction into borates. Interestingly, RbB₃O₄F₂ presents the novel [B₃O₄F₂]^- chains formed by the unprecedented [B₃O₅F₂]^3- fundamental building block. More importantly, RbB₃O₄F₂ has a large birefringence and a deep-UV cutoff edge. The finding of novel [B₃O₅F₂]^3- FBB and [B₃O₄F₂]^- chains in RbB₃O₄F₂ greatly enriches the structural diversity of fluorooxoborates.

Structural Diversity of Molybdate Iodate and Fluoromolybdate: Syntheses, Structures, and Calculations on Na3(MoO4)(IO3) and Na3Cs(MoO2F4)2

The alkali-metal molybdate iodate Na₃(MoO₄)(IO₃) (I) and mixed-alkali-metal fluoromolybdate Na₃Cs(MoO₂F₄)₂ (II) were obtained via a mild hydrothermal reaction using a "Teflon-pouch" method. I crystallizes in the triclinic space group P1, whose structure comprises a 3D backbone made up of isolated [IO₃]^- pyramids and [MoO₄]^2- tetrahedra connected via 5- and 6-fold coordinated sodium cations. II crystallizes in the monoclinic space group P2₁/c and comprises isolated [MoO₂F₄]^2- octahedra with strong out-of-center distortions and the Na⁺ as well as Cs⁺ cations acting as interstitial ions. Both compounds have been characterized by infrared (IR) spectra and ultraviolet-visible-near-infrared (UV-vis-NIR) diffuse reflectance spectra. First-principles calculations respectively reveal that they exhibit birefringence values with Δn = 0.078 and 0.210 at 1064 nm for I and II, and the origin of the birefringence is discussed.

Al8(BO3)4(B2O5)F8: A F-Containing Aluminum Borate Featuring Two Types of Isolated B-O Groups

Al₈(BO₃)₄(B₂O₅)F₈, as a new aluminum borate fluoride, has been synthesized by the high-temperature reaction with the closed system for the first time. With respect to its structure, the isolated BO₃ and B₂O₅ groups reside in the center and edge of tunnels constructed by the AlO₄F₂ polyhedra. The AlO₄F₂ polyhedra play the vital role on the formation of isolated B-O groups. According to our investigation, Al₈(BO₃)₄(B₂O₅)F₈ is the first case, which features two types of independently isolated B-O groups in the aluminum borate fluorides. Its cutoff edge is up to deep ultraviolet (DUV) range. What is more, the energy dispersive spectroscopy (EDS), infrared (IR) spectrum, and the first-principles calculations of Al₈(BO₃)₄(B₂O₅)F₈ have been performed.

Synthesis, characterization and crystal structure of a new mixed alkali and alkaline-earth metal borate Rb9Ba24(BO3)19

Rb₉Ba₂₄(BO₃)₁₉ features an intricate 3D Ba–O framework with three types of infinite channels where the Rb⁺ cations and isolated BO₃ units are located.

Pb3Ba3Zn6(BO3)8 and α-BaZn2(BO3)2: new members of the zincoborates containing two different dimensional Zn–O units

Two new zincoborates, namely, Pb₃Ba₃Zn₆(BO₃)₈ and α-BaZn₂(BO₃)₂, were synthesized by the high-temperature solution method and their structures were determined by single-crystal X-ray diffraction for the first time.

Prediction of ternary fluorooxoborates with coplanar triangular units [BOxF3−x]x− from first-principles

From first-principles prediction, we got all the basic structural units of fluorooxoborates, namely, tetrahedral elements [BO_xF_4−x] (x = 1,2,3) like [BO₄] and triangular elements [BO_xF_3−x] (x = 1,2) like [BO₃].

From BaAl2(BO3)2O to SnAl2(BO3)2F2: structure transformation based on ion regulation

Sn atoms reside in each Al–B–O–F channel consisting of Al₈B₈O₃₂F₁₂ cavities, which makes SnAl₂(BO₃)₂F₂ possess a special structure.

Sn2B7O12F with a 2∞[B14O24]6− layer constructed from the unprecedented [B7O16]11− fundamental building block

A new tin borate fluoride Sn₂B₇O₁₂F features a complicated 3D network composed of the unique [B₇O₁₆]¹¹⁻ FBBs and [Sn₄O₁₂F₂]¹⁸⁻ clusters.

Ba3B10O17F2·0.1KF: the first mixed alkali/alkaline-earth metal fluorooxoborate with unprecedented double-layered B–O/F anionic arrangement

The first mixed alkali/alkaline-earth metal fluorooxoborate Ba₃B₁₀O₁₇F₂·0.1KF with a unique double-layered B–O/F anionic framework was successfully synthesized and systemically characterized.

Na3B7O11F2: a new sodium-rich fluorooxoborate with a unique [B14O24F4] ring and a short ultraviolet absorption edge

A new sodium-rich fluorooxoborate Na₃B₇O₁₁F₂ features a novel large [B₁₄O₂₄F₄] ring formed by two corner-shared [B₇O₁₃F₂] groups, each containing two [B₃O₇] anionic units linked by a [BO₂F₂] group.

K2[B4O5(OH)4]·H2O and K2[B4O5(OH)4]: two new hydrated potassium borates with isolated [B4O5(OH)4]2− units and different structural frameworks

Two new hydrated potassium tetraborates with isolated [B₄O₅(OH)₄]²⁻ units were obtained via a mild hydrothermal method.

A new barium fluorooxoborate BaB5O8F·xH2O with large birefringence and a wide UV transparency window

By a cation substitution strategy, a new barium fluorooxoborate BaB₅O₈F was synthesized, which exhibits two interesting interpenetrating three-dimensional B–O/F frameworks and improved optical properties.

Mg(H2O)6B4O5(OH)4(H2O)3: a new hydrated borate with a short DUV cutoff edge

[B₄O₅(OH)₄] groups are linked together by hydrogen bonds forming undulating pseudo layers, leading to a short cutoff edge.

ABaSbQ3 (A = Li, Na; Q = S, Se): diverse arrangement modes of isolated SbQ3 ligands regulating the magnitudes of birefringences

The interrelation of arrangement modes of isolated SbQ₃ ligands on structures and birefringences has been systematically studied in series of chalcogenides.

Two new tin(iv)-containing phosphate fluorides with two types of Sn(iv)–P–O–F frameworks and short cutoff edges

Two new [SnOF] groups connect with the [P–O] group to form interesting structures.