Two Isostructural Multi-metal Borates: Syntheses, Crystal Structures and Characterizations of M_3LiNa_4Be_4B_(10)O_(24)F(M = Sr, Cd)

Two new isostructural multi-metal beryllium borates, m^3 Li Na4Be4B10O24F（M = Sr（1）, Cd（2））, have been synthesized by spontaneous crystallization. The structures were verified by single-crystal X-ray crystallography. The compounds crystallize in the trigonal space group R 3, with a = b = 9.4645（1） A, c = 38.842（8） A, V = 3013.2（6） A3, Z = 6, F（000） = 2568, Dc = 3.005 g/cm^3, Mr = 908.9, R = 0.0327, w R = 0.0678, μ = 8.160 mm-1 for Sr3 Li Na4Be4B10O24F and a = b = 9.3019（8） A, c = 37.782（7） A, V = 2831.12（9） A3, Z = 6, F（000） = 2748, Dc = 3.459 g/cm^3, Mr = 983.24, R = 0.0158, w R = 0.0455, μ = 3.586 mm-1 for Cd3 Li Na4Be4B10O24F. The structures are characterized by an infinite two-dimensional [Be8B16O40F2]∞ double layer bridged by [B12O24] groups like a sandwich structure, while the cations reside in tunnels along different directions. UV-vis-IR diffuse reflectance spectroscopy demonstrates that their cut-off edges are below 200 nm. Thermal analysis shows that they melt incongruently and their melting points are around 740-770 ℃.

Spectroscopy of compounds from the family of rare-earth orthoborates

This paper is devoted to the rare-earth borates described by the general formula RM3（BO3）4, M = Al, Fe, and Cr, that have non-centrosymmetric trigonal slructure of the natural mineral huntite. It give a brief review of a spectroscopic research on YbAI3（BO3）4 （YbAB）, on a large group of magnetic iron borates, and on NdCra（BO3）4.

Transformation Process and Mechanism of Lithium Borates

Amounts of lithium-containing salt lake brine resources are widely distributed in the four provinces named Qinghai,Tibet,Inner Mongolia and Xinjiang province,especially the salt lakes in Qinghai-Tibet Plateau are abundant of

Vibrational Spectroscopic Analysis of Borates in Mother Liquid of Brine after Potassium Separated

It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization

Processes on the Thermodynamic Properties of Lithium Borates

1 Introduction Lithium and its compounds as national strategic resources are extensively used in national defense,industrial and agricultural production.As we know,the salt lakes in the western of China are famous for its high

Syntheses and Crystal Structures of Two New Organically Templated Borates:[(C_2H_(10)N_2)]2[B_(14)O_(20)(OH)_6] and [C_8H_(22)N_4][B_5O_6(OH)_4]_2

Two new nonmetal borates, [（C2H10N2）]2[B14O20（OH）6] 1 and [C8H22N4][B5O6（OH）4]2 2, have been synthesized under mild conditions and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis and thermogravimetric analysis. Crystal data for compound 1： triclinic, space group P^-1, a = 8.4979（17）, b = 8.8498（18）, c = 10.065（2）A^°, α = 95.01（3）, β = 96.99（3）, γ = 116.82（3）°, V= 661.8（3）A^°^3, Z= 1, Mr = 697.63, Dc = 1.751 g/cm^3,μ = 0.163 mm^-1, F（000） = 356, the final R = 0.0372 and wR = 0.0968 （I 〉 2σ（I））; and those for compound 2： monoclinic, space group P21/c, a = 9.1867（18）, b= 14.118（3）, c = 10.334（2）A^°, β = 91.48（3）°, V = 1339.8（5）A^°^3, Z = 2, Mr = 610.46, Dc = 1.513 g/cm^3,μ = 0.135 mm^-1, F（000） = 632, the final R = 0.0350 and wR = 0.0912 （I 〉 2σ（I））. For both 1 and 2, the anionic units are interlinked via O-H…O hydrogen bonds to form a 3D supramolecular network, while the protonated cations are located in the free space of the inorganic borate framework and interact with the anions by electrostatic attraction and extensive N-H…O hydrogen bonds.

Friction and wear performances of borates and lanthanum chloride in water

The antiwear and friction-reducing performances of sodium borate, potassium borate and lanthanum chloride in water were evaluated on a four-ball friction tester. The topographies, element distribution and chemical characteristics of the worn surfaces were investigated by scanning electron microscope （SEM）, energy dispersion of X-ray （EDX） and X-ray photoelectron spectroscope （XPS）. The results indicated that sodium borate, potassium borate and lanthanum chloride increased extreme pressure, antiwear and friction-reducing capacities of water to a certain extent, of which potassium borate was the best candidate. Combination of lanthanum chloride with sodium borate and po- tassium borate respectively further improved antiwear and friction-reducing capacities. Scratches of worn surfaces lubricated with water containing borates and lanthanum chloride were less severe than those lubricated with water containing borates alone. A tribochemical film mainly composed of oxides of lanthanum, boron and iron reduced friction and wear for water lubricant formulated with both borates and lanthanum chloride.

Solvothermal Syntheses and Crystal Structures of Two New Nonmetal Borates:C_4H_(10)N_2·B_6O_8(OH)_2 and (NH_3CH_2CH_2NH_3)B_5O_8(OH)

Two new borate compounds, C4H10N2·B6O8（OH）2 and （NH3CH2CH2NH3）B5O8 （OH）2, have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, elemental analysis and thermal analysis. Compound 1 crystallizes in the monoclinic system, space group P21/c, with a = 8.3318（17）, b = 6.2118（12）, c = 12.479（3） A, β = 108.96（3）°, V = 610.8（2） A^3, Mr = 313.02, Z = 2, 13,.= 1.702 g/cm^,/J = 0.150 mm^-1, F（000） = 320, R = 0.0387 and wR = 0.0924. Its layered structure is linked by infinite covalently coordinated neutral sheets with 3,20-membered window system, which are built up from alternative B6O8（OH）2 subunits donated by two piperzazine nitrogen donors. 2 crystallizes in monoclinic, space group Co, with a = 6.7207（13）, b = 11.481 （2）, c = 12.564（3）A,β = 95.25（3）°, V = 965.4（3） A^3, Mr = 261.18, Z = 4, Dc = 1.797 g/cm^3,/t = 0.164 mm^-1, F（000） = 536, R = 0.0396 and wR = 0.0752. Its oxoborate structure is generated from the sheets of 3,9-membered boron rings bonded diamine molecules through electrostatic and H-bonding interactions to form a two-dimensional layered network.

Properties of a High Hydrolysis Stable Nitrogenous Benzo-heterocyclic Borates

A benzotriazole-containing derivative was synthesized via the Mannich reaction.The structure was characterized by NMR spectroscopy.By utilizing computational chemistry and molecular simulation,the calculation and mapping of atomic charge and frontier molecular orbitals with complex structure of the borate were carried out.The acid number of BTBE(nitrogen-containing heterocyclic borate)was determined by the standard test method for acid number and the open observation method.The results showed that BTBE had a low initial acid number,because the acid number was changed only after 72 hours of hydrolysis,and it was negative after the hydrolysis reached 120 hours.The extreme-pressure friction resistance of BTBE and other four base oils was also determined.For 5 kinds of base oils,the friction experiment was carried out under a load of 30 kgf,and the BTBE showed a lowest wear scar diameter(0.365 mm)along with a highest maximum non-seizure load.The results showed that the EP friction resistance of BTBE was stronger than that of other four base oils under the same test conditions.The results of hydrolysis performance showed that the synthesized nitrogencontaining heterocyclic borate had a high resistance to hydrolysis,while demonstrating broad application prospects.

Recent progress in ultraviolet and deep-ultraviolet nonlinear optical aluminoborates

Aluminoborates(ABOs)show wide ultraviolet(UV)transmittance,and are one of the important types of UV and deep-UV nonlinear optical(NLO)materials.In recent years,the combination of AlO_(n)(n=4,5,6)polyhedra or their fluorinated analogues with different polyborate anions leads to a rich variety of crystalline ABOs.In this review,we summarize the recent developments of UV and deep-UV NLO inorganic ABOs.These ABOs can be grouped into three types in terms of their compositions:(i)aluminum oxyborates,(ii)alkali/alkaline earth metal aluminoborates,and(iii)alkali/alkaline earth metal aluminoborate fluorides and fluoroaluminoborates.We discuss the synthesis,structural features,NLO properties,as well as related structure-performance relationships of these non-centrosymmetric ABOs.Finally,the future perspectives in this field are discussed.

Interface engineering strategy via electron-defect trimethyl borate additive toward 4.7 V ultrahigh-nickel LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)battery

The Li metal battery with ultrahigh-nickel cathode(LiNi_(x)M_(1-x)O_(2),M=Mn,Co,and x≥0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/kg.However,the practical application is impeded by the instability of electrode/electrolyte interface and Ni-rich cathode itself.Herein we proposed an electron-defect electrolyte additive trimethyl borate(TMB)which is paired with the commercial carbonate electrolyte to construct highly conductive fluorine-and boron-rich cathode electrolyte interface(CEI)on LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)surface and solid electrolyte interphase(SEI)on lithium metal surface.The modified CEI effectively mitigates the structural transformation from layered to disordered rock-salt phase,and consequently alleviate the dissolution of transition metal ions(TMs)and its“cross-talk”effect,while the enhanced SEI enables stable lithium plating/striping and thus demonstrated good compatibility between electrolyte and lithium metal anode.As a result,the common electrolyte with 1 wt%TMB enables 4.7 V NCM90/Li cell cycle stably over 100 cycles with 70%capacity retention.This work highlights the significance of the electron-defect boron compounds for designing desirable interfacial chemistries to achieve high performance NCM90/Li battery under high voltage operation.

Rhodium-Catalyzed Direct C-H Alkenylation of Indoles with Alkenyl Borates

Main observation and conclusion A new Rh(Ⅲ)-catalyzed direct C—H alkenylation of 2,3-unsubstitued indoles with alkenyl borates through C—H activation followed by transmetallation was described.This protocol provides an efficient method for the synthesis of terminal C2-alkenylindoles under mild conditions,and also shows broad substrate scope and high functional group tolerance with respect to both components.Furthermore,the C2-alkenylated indole can be easily transformed into carboline derivative,which is an important polycyclic indole moiety in natural products and drug molecules.

AN INVESTIGATION ON BORATES FROM NATURAL BRINES

Many kinds of borate can be obtained from salt-water solution of different compositions by artificial synthesis. However, borates have not yet been found in any evaporation process of natural B-bearing brines. M. G. Valyashko obtained 'eutecticborate' （MgO·B2O3·×H2O） from eutectic saturation brine （B2O3:1.2%） after 4-year reservation.

Lanthanide Inorganic Solids Based on Main Group Borates and Oxyanions of Lone Pair Cations

Lanthanide borates containing post transition metal main group elements, including Ga（Ⅲ）, Ge（Ⅳ）, Sb（Ⅴ） and Te（Ⅵ）, as well as lanthanide salts of the oxyanions of lone pair cations, such as I（Ⅴ）, Se（Ⅳ） and Te（Ⅳ）, were reviewed. The post transition metal main group elements in lanthanide borates adopt octahedral or tetrahedral geometry only. In the structure of lanthanide galloborates, only octahedral GaO6 was found while both octahedral GeO6 and tetrahedral GeO4 appeared in borogermanates. The fifth period elements Sb（Ⅴ） and Te（VI） prefer octahedral coordination geometry in lanthanide borates system. The second groups introduced to lanthanide oxyanions of lone pairs are mainly focused on do TM units, such as WO4 tetrahedron, VO5 square pyramid or MoO6 octahedron, and rigid tetrahedral groups like sulfate SO4, silica SiO4 or selenate SeO4 units. Divalent cations like Pb（Ⅱ） and magnetic ions of Cu（Ⅱ） or Mn（Ⅱ） were also included. The structure chemistry of lanthanide ions in these systems is rich. Coordination numbers from six to ten are discovered, yielding a wide range of coordination geometries including the pentagonal bipyramid, square antiprism, metabidiminished icosahedron, tricapped trigonal prism, capped triangular cupola, etc. The connectivity modes between the Ln polyhedra are miscellaneous, from 3D network, to 2D layer, 1D chain, tetramer, trimer, dimer and finally monomer. A number of compounds display NCS structures and strong SHG response, and many lanthanide compounds exhibit good luminescent properties in visible and IR region.

Two New Borates Built by Different Types of{B_(9)}Cluster Units

Two new belt-like borates Na_(4)[B_(9)O_(14)(OH)_(3)]·0.5H_(2)O(1)and Na_(5)[B_(9)O_(14)(OH)_(4)](2)have been synthesized under solvothermal conditions.Both compounds contain unprecedented B_(9)O_(16)(OH)_(n)^((n+5))−[n=3(1),4(2)]clusters,which are constructed from four B_(3)O_(3) rings via three BO_(4) tetrahedra.Compound 1 exhibits a rare 1D belt with two types of 8-membered ring(MR)windows based on B_(9)O_(16)(OH)_(3)^(8−) clusters.Compound 2 features two different 1D belts built by different B_(9)O_(16)(OH)_(4)^(9−) units,which is first discovered in borate family.UV-Vis diffuse reflectance spectra reveal that compounds 1 and 2 have the cut-off edges below 190 nm,indicating that they may have potential application in deep UV(DUV)region.

Rb_(5)Ba_(2)(B_(10)O_(17))_(2)(BO_(2)):The formation of unusual functional [BO_(2)]^(-) in borates with deep-ultraviolet transmission window

The design and synthesis of new deep-ultraviolet(DUV)optical materials are important but challenging.It is well known that the polarizability anisotropy of linear[BO_(2)]^(−)is larger than those of[BO_(3)]^(3−)and[BO_(4)]^(5−),which is the better choice for exploring excellent optical materials.Here,we search for such crystals in borate systems based on the unusual fundamental structural unit[BO_(2)]^(−).By combining the linear[BO_(2)]^(−)with the traditional triangular[BO_(3)]^(3−)and tetrahedral[BO_(4)]^(5−)units,a new mixed metal borate,Rb_(5)Ba_(2)(B_(10)O_(17))_(2)(BO_(2))was obtained via high-temperature solution method.It exhibits excellent optical properties including a DUV transmission window(188 nm)and suitable birefringence(0.06).It also has good thermal stability and its crystal plates can be prepared easily.Furthermore,the strategies of designing borates with[BO_(2)]^(−)units have been proposed from the transformation of crystal framework and the preparation method.

Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D{B5}/{B6}Helical Chains

Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm.

In vitro polymerization of the dopamine-borate melanin precursor:A proof-of-concept regarding^(10)boron neutron-capture therapy for melanoma

The^(10)boron neutron-capture therapy(BNCT)is an emerging antitumoral method that shows increasing biomedical interest.BNCT is based on the selective accumulation of the^(10)boron isotope within the tumor,which is then irradiated with low-energy thermal neutrons,generating nuclear fission that produces 7lithium,4helium,andγrays.Simple catechol-borate esters have been rather overlooked as precursors of melanin biosynthesis,and therefore,a proof-of-concept approach for using dopamine-borate(DABO)as a suitable boron-containing candidate for potential BNCT is presented here.DABO can spontaneously oxidize and autopolymerize in vitro,giving a soluble,eumelaninlike brown-black poly-DABO product.Melanotic melanoma cell cultures treated with 1 mM DABO for 24 and 48 h were viable and showed no signs of damage or cell death.The stability and possible trans-esterification of DABO is shortly discussed.Chemical calculations and quantitative structure-activity relationships(QSAR)analysis of DABO and the BNCT agent BPA indicated that they should be cell permeant and accumulate within lysosomes and melanosomes.Molecular modeling allows visualization of both the DABO precursor and the structure of a borate derivative of the proposed catechol-porphycene model for eumelanin,showing interesting features from molecular orbital calculations.The main difference between DABO and other agents,such as BPA,is that it is not a boronic acid nor a boron cluster.This simple catechol-borate ester(protected from oxidation and blackening)could be administrated to living cells and organisms,in which biosynthesis of boron-melanin in melanoma melanocytes can lead to improved BNCT.

Experimental and ab initio study of Ba_(2)Na_(3)(B_(3)O_(6))_(2)F stability in the pressure range of 0–10 GPa

Both numerical and experimental studies of the stability and electronic properties of barium–sodium metaborate Ba_(2)Na_(3)(B_(3)O_(6))_(2)F(P63/m) at pressures up to 10 GPa have been carried out. Electronic-structure calculations with HSE06 hybrid functional showed that Ba_(2)Na_(3)(B_(3)O_(6))_(2)F has an indirect band gap of 6.289 eV. A numerical study revealed the decomposition of Ba_(2)Na_(3)(B_(3)O_(6))_(2)F into the BaB_(2)O_(4),Na BO_(2), and NaF phases above 3.4 GPa at 300 K. Subsequent high-pressure high-temperature experiments performed using ‘Discoverer-1500’DIA-type apparatus at pressures of 3 and 6 GPa and temperature of 1173 K confirmed the stability of Ba_(2)Na_(3)(B_(3)O_(6))_(2)F at 3 GPa and its decomposition into BaB_(2)O_(4), NaBO_(2), and NaF at 6 GPa, which was verified by energy-dispersive X-ray analysis and Raman spectroscopy. The observed Raman bands of the Ba_(2)Na_(3)(B_(3)O_(6))_(2)F phase were assigned by comparing the experimental and calculated spectra. The experimental Raman spectra of decomposition reaction products obtained at 6 GPa suggest the origin of a new high-pressure modification of barium metaborate BaB_(2)O_(4).

High sintering and dielectric performance:The improved(Mg,Zn)_(3)B_(2)O_(6) ceramics with the help of the DFT calculation

With the help of the first principle calculation,the solid-state reaction experiment was conducted to investigate the alteration in the sintering and the microwave dielectric properties of Mg_(3)B_(2)O_(6)ceramic with many Zn^(2+)substitutions.These properties were characterized using the scanning electron microscopy,network analyzer,X-ray diffraction,Raman spectroscopy,energy-dispersive spectroscopy,and thermomechanical and differential-thermal analyses.The coexistence of Mg_(3)B_(2)O_(6),Mg_(2)B_(2)O_(5)and ZnO ceramics could be observed with increasing Zn^(2+)addition,and the lattice distortion occurred in the Mg_(2)B_(2)O_(5)and Mg_(3)B_(2)O_(6)ceramics due to the substitution of Mg^(2+)with Zn^(2+).The electron density and the bond property of the MgO_(6)octahedron changed,and a quantitative method was used to discuss the variation in sintering,substitution and phase formation properties.The densification window was decreased to 1100℃,and the dielectric properties improved with the formation of a three-phase borate solid solution(dielectric constant=6.73,quality factor=112,000 GHz at 16 GHz(Q=7000),temperature coefficient of resonant frequency=-61.2 ppm℃^(-1),and relative density=97.0%).