AYSO4F2 (A = K, Rb): [YO4F4] Polyhedra Enhancement of Birefringence in Non-π-Conjugated Sulfate Systems.

A mild hydrothermal method was employed to successfully synthesize two new sulfate fluorides, namely, AYSO4F2 (A = K, Rb). They are isomorphic, and both contain [YO4F4] polyhedra and [SO4] tetrahedra in the structure. Theoretical calculations and experimental tests show that AYSO4F2 (A = K, Rb) have large band gaps (7.79 and 7.82 eV) and moderate birefringence (0.015 and 0.02 @ 546.1 nm), with significantly enhanced birefringence and band gaps as compared to that of the single alkali metal sulfates A2SO4 (A = K, Rb). Furthermore, theoretical calculations show that [YO4F4] polyhedra are the main reason for the band gap and birefringence enhancement. This work contributes to the advancement of structural chemistry in the field of rare-earth sulfates, offering a novel approach for the design of sulfates characterized by large birefringence.

Na6Mg3P4S16 and RbMg2PS4Cl2: two Mg-based thiophosphates with ultrawide bandgaps resulting from [MgS6] and [MgSxCl6-x] octahedra.

Designing wide-bandgap chalcogenides is one of the most important ways of obtaining high-performance infrared (IR) functional materials. In this work, two Mg-based metal thiophosphates, namely Na6Mg3P4S16 (NMPS) and RbMg2PS4Cl2 (RMPSC), were successfully obtained by introducing [MgS6] and [MgSxCl6-x] octahedra into thiophosphates. In addition, their crystal structures were determined, a first for Mg-containing [PS4]-based thiophosphates to the best of our knowledge. Their bandgaps were investigated in theoretical ways and verified by taking experimental measurements, and determined to be 3.80 eV for NMPS and 3.93 eV for RMPSC, values greater than those of the other investigated thiophosphate halides. The wide bandgaps of NMPS and RMPSC were attributed, based on theoretical calculations, to the [MgSxCl6-x] (x = 0-6) octahedron.

Cd8(BO3)4SiO4: Metal Cation Inducing the Formation of Isolated [BO3] and [SiO4] Units in Borate Silicate.

The first compound of cadmium-borate silicate Cd8(BO3)4SiO4, crystallizing in space group P42/n (no. 86), has been successfully synthesized by the conventional high-temperature solution method and melts congruently. The zero-dimensional anionic groups of Cd8(BO3)4SiO4 are isolated [BO3] triangles and isolated [SiO4] tetrahedra which are filled in the framework formed by [CdO6] polyhedra. It has a moderate birefringence (Δn = 0.053 at 546 nm), which is measured by experiment and evaluated by first-principles calculations; meanwhile, the source of birefringence is revealed through the response electronic distribution anisotropy method. The UV-vis-NIR diffuse reflectance spectrum indicates that Cd8(BO3)4SiO4 possesses a wide optical transparency range, with a UV cutoff edge at about 254 nm. This work enriches the structure chemistry of borate silicates, and we discussed the possible methods for the exploration and synthesis of novel optical crystals possessing zero-dimensional anionic groups in the borate silicate system.

[RbSr3X][(BS3)2] (X = Cl, Br): two salt-inclusion thioborates with large birefringence and structure transformation from centrosymmetric to asymmetric.

[RbSr3X][(BS3)2] (X = Cl, Br), two salt-inclusion chalcogenides with planar [BS3] as anionic units, were obtained. Structure analysis indicates that the size effect of halogens may adjust the arrangement between the [BS3] units and further lead to the CS-to-NCS structure transformation. Experimental characterizations reveal that they have wide bandgaps (3.64-3.70 eV), large birefringence (0.136-0.144) and high LIDT (12-14 × AgGaS2). This work indicates that the thioborate family is a rich source to explore structure chemistry and promising infrared functional materials.

Hydroxyl-Driven Enhanced Birefringence in Borophosphates.

Borophosphates have become promising candidates for ultraviolet or deep-ultraviolet functional crystals. Through high-temperature solution method, four new borophosphates, K2B2P2O9, (NH4)2BP2O7(OH), K2BP2O7(OH), and P21/c-(NH4)2B2P3O11(OH), were acquired successfully. Single crystal X-ray diffraction suggests that K2B2P2O9, (NH4)2BP2O7(OH), and K2BP2O7(OH) belong to the noncentrosymmetric space group, while P21/c-(NH4)2B2P3O11(OH) belongs to the centrosymmetric compound. It is worth mentioning that K2B2P2O9, (NH4)2BP2O7(OH), and K2BP2O7(OH) present the new fundamental building blocks [B2P2O11], [BP2O10H], and [BP2O9(OH)], respectively, as far as we know. Compared with K2B2P2O9, (NH4)2BP2O7(OH), K2BP2O7(OH), and P21/c-(NH4)2B2P3O11(OH) exhibit a larger optical anisotropy, further confirming the positive effect of hydroxyl groups on birefringence. UV-vis-NIR diffuse reflectance spectra display that K2B2P2O9 and (NH4)2BP2O7(OH) have short UV cutoff edges. Meanwhile, theoretical calculations were conducted to comprehend their optical properties and electronic structures.

Vanadate Crystals with an Enhanced Birefringence and a Broadened Transparency Spectrum through Controlled [VO3]∞ Chain Arrangements and Alkali Metal Cation Introduction.

The vanadate (VO) polyhedron offers a compelling avenue for exploring birefringent materials within the infrared frequency range. Among many potential building blocks, the implementation of [VO3]∞ chains demonstrated great potential as effective birefringent functional units. In this article, we successfully synthesized the Li0.8Na0.2CsV2O6·H2O compound, which exhibits a remarkable birefringence of 0.134 at 546.1 nm, as confirmed by the experiment. Notably, the introduction of alkali metals in this compound led to a significantly shorter cutoff edge at 340 nm. Through a comprehensive investigation, Li0.8Na0.2CsV2O6·H2O has the shortest UV cutoff edge among all vanadates, whose birefringences are larger than 0.1, to the best of our best knowledge. This finding underscores the application potential of this novel material as a birefringent crystal.

K5[B3O3F4(OH)]2(NO3): the first hydroxyfluorooxoborate-nitrate with a short ultraviolet cutoff edge and large birefringence.

The first hydroxyfluorooxoborate-nitrate mixed anion compound, K5[B3O3F4(OH)]2(NO3), was synthesized by the solution evaporation method. It displays a unique structure built by K+ cations, the hydroxylated and fluorinated six-membered ring [B3O3F4(OH)] and [NO3] groups. It possesses a band gap of 5.68 eV derived from the diffuse reflectance spectrum, which corresponds to an ultraviolet cutoff edge of 218 nm. First-principles calculations show that it has a large birefringence of 0.095 at 532 nm and the result of the response electron distribution anisotropy method indicates that all three anion groups contribute positively to the birefringence, verifying the synergic contributions from the multiple anion groups.

Li2RbSO4Cl with a Short Ultraviolet Absorption Edge and an Acentric Structure through Assembling Heteroleptic [LiO3Cl] Tetrahedra.

Currently, short-wavelength nonlinear optical materials are urgently needed. Through substituting homoleptic [LiO4] in centrosymmetric LiRbSO4 with heteroleptic [LiO3Cl] tetrahedra, an acentric sulfate chloride, Li2RbSO4Cl, was designed and synthesized by the high-temperature melting method. Li2RbSO4Cl shows a relatively short ultraviolet absorption edge (<200 nm) among newly reported sulfate chlorides. Millimeter-sized crystals were grown due to the congruent melting behavior and high thermal stability of the compound.

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

Three polyborates, namely, LiNa11B28O48, Li1.45Na7.55B21O36, 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]. Li1.45Na7.55B21O36 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 Li1.45Na7.55B21O36, 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.

Stereochemically Active Tin(II)-Induced Enhancement of Birefringence in SnII SnIV (PO4 )2 and SrSn(PO4 )PO2 (OH)2.

Two new tin(II) phosphates, SnII SnIV (PO4 )2 and SrSn(PO4 )PO2 (OH)2 , were synthesized by the high-temperature solution method and hydrothermal method, respectively. Theoretical study indicates that by introducing tin(II) with stereochemical activity lone pairs (SCALP) in metal phosphates, the birefringence was enhanced, 0.048@1064 nm for SnII SnIV (PO4 )2 and 0.080@1064 nm for SrSn(PO4 )PO2 (OH)2 .

Target-Oriented Synthesis of Borate Derivatives Featuring Isolated [B3O3] Six-Membered Rings as Structural Features.

Borates provide an excellent platform for investigating the optical nonlinearity and linearity of crystals as photoelectric functional materials. In our work, borate derivatives with isolated [B3O3] six-membered rings as structural features are the preferred system due to their simple functional units and excellent properties. Herein, by utilizing the target-oriented synthesis, a series of borate derivatives, A2[B3O3F4(OH)] (A= NH4, Rb, Cs) (ABOFH), K2.3Cs0.7B3O3F6 (KCsBOF), and Cs3[B3O3(OH)3]Cl3 (CsBOHCl), with novel heteroanionic groups containing [BOxF4-x] (x = 0-3) and/or [BO2(OH)] units were obtained. ABOFH, KCsBOF, and CsBOHCl construct different two-dimensional pesudolayers featuring [B3O3F4(OH)], [B3O3F6], and [B3O3(OH)3] units, respectively. Also, the optical properties and the arrangement information of these anionic groups were studied. Among the total five compounds, (NH4)2[B3O3F4(OH)] and Cs3[B3O3(OH)3]Cl3 with enlarged birefringence and sufficient band gaps were screened out as promising birefringent crystals due to the optimally aligned configuration of birefringence-active heteroanionic units. The successful results of target-oriented synthesis indicate a more profound conclusion that the borate system now has more diversified structural chemistry, and an effective strategy was proposed to modify the arrangement and species of anionic units to optimize the performance of optical crystals.

Birefringence Regulation by Clarifying the Relationship Between Stereochemically Active Lone Pairs and Optical Anisotropy in Tin-based Ternary Halides.

It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A3 SnCl5 and ASn2 Cl5 (A=NH4 and Rb) have been synthesized successfully. The experimental birefringence of Rb3 SnCl5 and RbSn2 Cl5 is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials.

Recent Development of SnII , SbIII -based Birefringent Material: Crystal Chemistry and Investigation of Birefringence.

The combination of SnII or SbIII with π, non-π-conjugated units has produced birefringent crystals with birefringence ranging from 0.005 to 0.468@1064 nm. It is proven that introducing SnII or SbIII into crystals is a feasible strategy to enlarge the birefringence, which not only promotes the miniaturization of fabricated devices, but also effectively modulates polarized light. Herein, recently discovered SnII , SbIII -based birefringent crystals with birefringence investigated are summarized, including their crystal structure and optical properties, especially birefringence. This review also presents the influence of SnII , SbIII with stereochemically active lone pair on the optical anisotropy. We hope that this work provides a clear perspective on the crystal chemistry of SnII , SbIII -based optical functional crystals and promotes the development of new birefringent crystals with large optical anisotropy.

Target-Driven Design of Deep-UV Nonlinear Optical Materials via Interpretable Machine Learning.

The development of a data-driven science paradigm is greatly revolutionizing the process of materials discovery. Particularly, exploring novel nonlinear optical (NLO) materials with the birefringent phase-matching ability to deep-ultraviolet (UV) region is of vital significance for the field of laser technologies. Herein, a target-driven materials design framework combining high-throughput calculations (HTC), crystal structure prediction, and interpretable machine learning (ML) is proposed to accelerate the discovery of deep-UV NLO materials. Using a dataset generated from HTC, an ML regression model for predicting birefringence is developed for the first time, which exhibits a possibility of achieving fast and accurate prediction. Essentially, crystal structures are adopted as the only known input of this model to establish a close structure-property relationship mapping birefringence. Utilizing the ML-predicted birefringence which can affect the shortest phase-matching wavelength, a full list of potential chemical compositions based on an efficient screening strategy is identified. Further, eight structures with good stability are discovered to show potential applications in the deep-UV region, owing to their promising NLO-related properties. This study provides a new insight into the discovery of NLO materials and this design framework can identify desired materials with high performances in the broad chemical space at a low computational cost.

Chain-like [Sx ] (x=2-6) Units Realizing Giant Birefringence with Transparency in the Near-Infrared for Optoelectronic Materials.

Birefringent crystals are requisite optical devices in laser and modern opto-electronic fields. Development of excellent birefringent materials is still challenging. Herein, the linear or chain-like [Sx ] (x=2-6) species were theoretically proved to be the origin of the large birefringence, and could be regarded as birefringent genes. Besides, the metal polysulfide family was first proposed to be rich birefringent materials source, among which Cs2 S6 realizes giant birefringence 0.58@1064 nm together with a wide band gap of 1.70 eV (based on the generalized gradient approximation). Moreover, the first dual-anion group polysulfide Na4 Ba3 (S2 )4 S3 was obtained, showing wide infrared transmission range (0.5-6.2 µm), wide band gap (2.3 eV), and large birefringence (0.37 at 1064 nm). This work provides a new guiding thought for exploring large birefringence crystals in the future.

LiCs3AlB7O14: achieving enhanced optical anisotropy via [AlO4] tetrahedron introduction to rearrange the anionic framework.

Borate has become a hot topic because of its rich structural chemistry and excellent properties for functional materials fields. The rearrangement of π-conjugated B-O units is key to enhancing the optical anisotropy, but it remains a challenge. Herein, by introducing [AlO4] tetrahedra, a new congruent melting aluminoborate LiCs3AlB7O14 with [B7O14] clusters was discovered. This work confirms that the introduction of [AlO4] tetrahedra can lead to the rearrangement of anionic framework of the borate system and thereby enhance the birefringence of LiCs3AlB7O14. The birefringence is about 4.1 times higher than that of its congener Li4Cs3B7O14 with the same [B7O14] clusters. Similarly, the effects of [AlO4] tetrahedra on the rearrangement of the B-O anionic framework are also demonstrated in other known borates.

Study on Coated Zr-V-Cr Getter with Pore Gradient Structure for Hydrogen Masers.

As the core component of satellite navigation, the hydrogen maser needs a high vacuum environment to maintain the stability of the frequency signal. The getter pump, composed of various non-evaporable getters, plays an important role in maintaining the high vacuum. In this paper, the Zr100-xCux (x = 0, 2, 4, 6)/Zr56.97V35.85Cr7.18 getter was studied and the contradiction between sorption performance and mechanical properties was solved. The Zr-V-Cr getter, a better candidate for getter pump, exists for problems which will destroy the high vacuum and affect the service life of the hydrogen maser. To solve the problem of dropping powder from Zr-V-Cr getter, Zr-Cu films were coated on the surface of Zr-V-Cr matrix to obtain the pore gradient structure. After vacuum sintering, the interface showed gradient structure and network change in pore structure from Zr-Cu film to Zr-V-Cr matrix. These characteristic structures made Zr-V-Cr getter have good absorption properties, which is better than a similar product of SAES company and mechanical properties. Because the Zr-Cu film on Zr-V-Cr matrix effectively prevented dropping powders from the matrix, (Zr-Cu)/(Zr-V-Cr) getter solved the problem of dropping powder. The self-developed new getter with pore gradient structure is of great significance for maintaining the high vacuum of hydrogen maser in the future.

A bibliometrics analysis and visualization of osteoimmunology on osteoarthritis studies.

BACKGROUND: Osteoarthritis (OA), the most prevalent form of arthritis, which affects up to 15% of the adult population. The work presented in this paper focuses on the analysis of the publications on osteoimmunology of OA. The purpose of this paper is to provide inspiration for future research on osteoimmunology of OA. METHODS: We extracted all of the English publications relevant to osteoimmunology of OA published from 1991-2020 from the Web of Science. SPSS, GraphPad Prism, Citespace, and VOSviewer were utilized to collect and analyze the publication trends in osteoimmunology of OA. RESULTS: We identified a total number of 1,004 publications with a total number of citations of 35,675 by October 31, 2020. Most publications came from China (26.8%). The United States ranked second, but its average number of citations and H index ranked best (10,130 citations and 55 H-index). Shandong University is the main center of institutional cooperation. Most papers related to osteoimmunology of OA were published in the journal of Osteoarthritis and Cartilage. In this field, TAK PP published the most papers (15), while Kotake, S's article was cited the most frequently (1,195). As presented in Figure 6, the 70 keywords, defined as terms that appeared more than 50 times in all papers, were classified into four clusters molecular research, human research, animal research and cell research. Research on cytokines and pathways is the new trend in Molecular research. CONCLUSION: The current status and global trend of osteoimmunology of OA revealed by this study indicates that there is a strong possibility that the number of papers will increase in the coming year, and the research on cytokines as well as pathways would be the next hot topic.

Quality Assessment of Artemisia rupestris L. Using Quantitative Analysis of Multi-Components by Single Marker and Fingerprint Analysis.

The chromatographic fingerprint of 14 batches of Artemisia rupestris L. samples were established in this study. The constituents of ten components in Artemisia rupestris L. were determined using quantitative analysis of multi-components by single marker (QAMS) and the external standard method (ESM). Due to their stability and accessibility, chlorogenic acid and linarin were used as references to calculate the relative correction factors (RCFs) of apigenin-C-6,8-pentoside-hexoside, apigenin-C-6,8-di-pentoside, luteolin, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid, chrysosplenetin B, and sbsinthin, based on high-performance liquid chromatography (HPLC). The value calculated by QAMS was consistent with that of the ESM, and the reproducibility of RCFs was found to be reliable. In conclusion, simultaneous determination of the ten components by the QAMS method and chromatographic fingerprint analysis were feasible and accurate in evaluating the quality of Artemisia rupestris L. and can be used as reference in traditional Chinese medicine quality control.

A new strategy based on PCA for inter-batches quality consistency evaluation.

Due to cultivation position, climate, harvest times, storage conditions and processing method, the evaluation of intra- and inter- batches quality consistency of botanical drugs has always been a thorny problem since it concerns safety and efficacy. The combination of fingerprint based on instrumental analysis and chemometrics is a common evaluation method in recent years. The differences between groups can be judged intuitively and superficially through principal component analysis (PCA) multi-dimensional score plots, but there is a lack of scientific and quantitative index to quantify the differences between groups. How to quantify the difference between groups is basically a blank area of research. Based on traditional F-statistic, we proposed a new F*-statistic to quantify the difference between groups in PCA score plots from the perspective of statistics. As the results revealed, the calculated F*-statistic was 2.58, smaller than the critical value 3.17 (α = 0.05), which indicated that there was no significant difference between groups. Our study add another dimension for PCA application, which offers a new strategy to quantify differences between groups by a new perspective, namely, a combination of fingerprint, chemometrics and statistics to evaluate inter-batches quality consistency quantitatively and objectively. Therefore, this manuscript could provide new ideas and technical references for the quality consistency evaluation of natural drugs, thus better guarantee their clinical efficacy and safety, and better promote industrial development.