FT-IR spectroscopic study of phase transformation of chloropinnoite in boric acid solution at 303 K

The dissolution and transformation of chloropinnoite in boric acid solution at 303 K has been studied using FT-IR difference spectroscopic technique. After equilibrium was reached, liquid and solid phases were separated and FT-IR spectra of each phase were recorded, FT-IR spectroscopic analysis of solid phases indicated that the transformation products, with the increase of boron-concentration in solution, were 2MgO x 3B2O3 x 15H2O (inderite), 2MgO x 3B2O3 x 15H20 (kumakovite), MgO x 3B2O3 x 7.5H2O, and MgO x 3B2O3 x 7H2O, respectively. The main polyborate anions and their interaction in each borate saturated aqueous solution have been proposed according to the FT-IR difference spectra of borate in liquid phase, and some assignments were tentatively given firstly. The relations between the existing forms of polyborate anions and the crystallizing solid phases have been gained.     

Investigations of kinetics and mechanism of chloropinnoite in boric acid aqueous solution at 303 K by Raman spectroscopy

Raman spectroscopy of dissolution and transformation of chloropinnoite in 4.5% (wt.%) boric acid aqueous solution at 303 K has been recorded. The Raman spectra of kinetics process have been obtained. The phase transformation product is 2MgO.3B2O3.15H2O (kurnakovite). The main polyborate anions and their interaction in aqueous solution have been proposed according to the Raman spectrum. Some assignments were tentatively given and the relations between the existing forms of polyborate anions and the crystallizing solid phases have been gained. A mechanism of dissolution and crystallization reactions and the formation condition of kurnakovite in Qinghai-Tibet plateau were proposed and discussed.     

过饱和硼酸盐水溶液的Raman光谱

制备了MgO·2B₂O₃-H₂O,Na₂O·5B₂O₃-H₂O和MgO·3B₂O₃-H₂O的过饱和水溶液.采用激光喇曼光谱研究了这些过饱和水溶液,并对光谱频率进行了归属.讨论了过饱和水溶液中硼氧配阴离子的存在形式和相互作用机理.     

MgO·3B2O3·3.5H2O的合成、表征及其溶液Raman光谱分析

硼是具有独特化学行为的稀有亲氧元素，在自然界中主要是以无机硼氧酸和硼氧酸盐形式存在。在硼酸盐晶体中，硼以聚合硼氧配阴离子形式存在，其中配位数为３和４的硼原子比可以有所不同，这使得硼酸盐种类繁多，结构复杂多样。至今，人们在自然界和实验室已发现了４种六硼酸镁盐犤１，２犦：MgO·３B２O３·nH２O（n＝７．５，７，６，５），它们的分子结构中都含有犤B６O７（OH）６犦２－基团。最近，我们在硼酸盐化学系列研究中，利用复盐氯柱硼镁石在沸点温度下的硼酸溶液中的相转化，合成了一种新的六硼酸镁盐MgO·３B２O３·３．…     

水合铵硼氧酸盐及其饱和溶液的FTIR和Raman光谱研究

研究了NH₄B₅O₈·4H₂O和(NH₄)₂B₈O₁₃·6H₂O及其饱和溶液于20℃的FTIR和Raman光谱,对振动频率进行了归属.根据振动光谱特征,预测(NH₄)₂B₈O₁₃·6H₂O中所含基本结构单元为[B₇O ₁₁(OH)·B(OH)₃]^2-.首次将Raman光谱中516cm^-1处的强散射峰归属为这一多聚硼氧配阴离子的对称脉冲振动峰,并对以上2种铵硼氧酸盐饱和溶液中硼氧配阴离子的存在形式{B(OH)₃,[B₃O₃(OH)₄]^-和[B₅O₆(OH)₄]^-}和相互作用机理进行了探讨.     

硼酸镁过饱和水溶液稀释和酸化过程中的Raman光谱

用纯水和恒沸点盐酸对六硼酸镁过饱和水溶液进行稀释和酸化,使用激光Raman光谱记录反应过程。对光谱峰进行归属。讨论了溶液中含硼量和pH值对硼氧配阴离子存在形式的影响,对多聚硼氧配阴离子在溶液中的存在形式及其相互作用机理进行了初步探讨。     

Raman spectroscopic analysis of supersaturated aqueous solution of MgO.B2O3-32%MgCl2-H2O during acidification and dilution

Raman spectra of supersaturated aqueous solution of MgO.B2O3-32%MgCl2-H2O during acidification/alkalization and dilution have been studied. The assignments of the recorded Raman shift are given. The main existing forms of polyborate anions and their interaction in borate aqueous solution have been proposed through spectroscopic analysis. The experimental results indicate that the higher concentration of cation are beneficial not only to the dissolution of boric acid but also to the polymerization of polyborate anions. The existing forms and interaction among them also depend on the concentration of boron and the pH value in solution.     

FT-IR spectroscopy of supersaturated aqueous solutions of magnesium borate

FT-IR spectra of supersaturated aqueous solution of magnesium borate, its acidized solutions with azeotropic hydrochloric acid, and its diluted solutions with water have been recorded. The FT-IR spectra of borate in solution are obtained by difference, subtracting the FT-IR spectrum of water from that of the magnesium borate supersaturated aqueous solution. All of the results showed that various polyborate anions in the supersaturated aqueous solutions exist. The bands of symmetric pulse vibration of the corresponding polyborate anions were indicated and some assignments were tentatively given.     

NaB5O8·5H2O过饱和溶液中硼氧配阴离子的FT-IR光谱分析

研究了NaB₅O₈·5H₂O过饱和水溶液及其在稀释和酸化过程中的FT-IR光谱,并与已知固体五硼酸盐对比进行光谱频率的归属,提出五硼酸盐过饱和水溶液中硼氧配阴离子的存在形式及其相互转化机理。     

盐卤硼酸盐化学──ⅩⅩⅧ.氯柱硼镁石的激光拉曼光谱

本文研究了氯柱硼镁石硼酸和硼砂的晶体和它们在水溶液中的激光拉曼光谱，并与某些阴酸盐的谱图进行对比．初步提出硼氧配阴离子的聚合形式，为进行氯柱硼镁石结构分析提供实验依据．     

Synthesis and structural characterization of an unprecedented nonmetal cation polyborate salt containing two different "isolated" polyborate anions: [H2en]2[B4O5(OH)4][B7O9(OH)5]·3H2O (en = H2NCH2CH2NH2)

The nonmetal cation polyborate salt of stoichiometry [H(2)en](2)[B(11)O(18)(OH)]·7H(2)O is obtained from the reaction of 1,2-diaminoethane and boric acid (1:5 ratio) in H(2)O/MeOH. An X-ray crystallographic study of the product reveals that the polyborate moiety is composed of two isolated hydrated polyborate anions: [B(4)O(5)(OH)(4)](2-) and [B(7)O(9)(OH)(5)](2-). The structure is templated by the cations with the anions forming a supramolecular H-bonded network, augmented by additional H-bonds involving the waters of crystallization and the cations.     

Synthesis, Spectroscopic Properties and Crystal Structure of (C_4N_2H_(12))_2Zr(C_2O_4)_4·H_2O

1 INTRODUCTION The researches on transition metal coordination complexes have been rapidly expanded because of their fascinating structural diversity and potential applications[1～4]. As we know, zirconium oxalates can be used as precursors in the synth…     

Synthesis,Spectroscopic Properties and Crystal Structure of (C4N2H12)2Zr(C2O4)4·H2O

The title compound (C4N2H12)2Zr(C2O4)4·H2O 1 was synthesized by the reaction of ZrOCl2·8H2O, H2C2O4·2H2O and piperazinium in aqueous solution. Single-crystal X-ray analysis has revealed that compound 1 (C16H26N4O17Zr, Mr = 637.63) crystallizes in the monoclinic system, space group P21/c with a = 9.0425(3), b = 13.3844(3), c = 19.1191(5)A, β = 98.365(1)o, V = 2289.34(11) A3, Z = 4, Dc = 1.850 g/cm3, F(000) = 1304, μ = 0.577 mm-1, the final R = 0.0240 and wR = 0.0628 for 4386 observed reflections with I > 2σ(I). X-ray crystal-structure analysis suggests that compound 1 consists of [Zr(C2O4)4]4- anion and two protonated piperazinium cations. The anions are linked through hydrogen bonds of piperazinium. FT-IR and Raman spectra clearly show the existence of oxalate groups in the crystal lattice.     

Cesium hydridotris(trifluoromethyl)borate, Cs[(CF3)3BH

Treatment of Cs[(CF3)3BNH2] with the aminating agent H2NOSO3H in aqueous solution allowed the isolation of pure Cs[(CF3)3BH], which is stable up to 300 degrees C. Due to the strong electron-withdrawing effect of the CF3 substituents, the [(CF3)3BH]- anion behaves as a very unreactive hydride. It is stable in concentrated hydrochloric acid for many days but reacts cleanly with F2, Cl2, and Br2 to the corresponding haloborates. The molecular structure was determined by single-crystal X-ray diffraction. Crystal data: orthorhombic, space group Pnma; a = 11.4296(5) A, b = 7.9510(4) A, c = 9.7268(5) A; V = 883.94(7) A(3), Z = 4; R1 = 0.0294, wR2 = 0.0818. The anions exhibit only Cs symmetry in the lattice. The natural and deuterated anions were characterized by IR, Raman, and multinuclear NMR spectroscopy; vibrational assignments were supported by DFT calculations. QTAIM charges derived from the B3LYP electron density are given for [(CF3)3BH]- and several related anions.     

盐卤硼酸盐化学──ⅩⅩⅧ.氯柱硼镁石的激光拉曼光谱

本文研究了氯柱硼镁石硼酸和硼砂的晶体和它们在水溶液中的激光拉曼光谱,并与某些阴酸盐的谱图进行对比.初步提出硼氧配阴离子的聚合形式,为进行氯柱硼镁石结构分析提供实验依据.     

Raman,infrared and force field studies of K2(12)C2O4 x H2O and K2(13)C2O4 x H2O in the solid state and in aqueous solution,and of (NH4)2(12)C2O4 x H2O and (NH4)2(13)C2O4 x H2O in the solid state

The Raman and infrared spectra of solid K2(12)C2O4 x H2O are reported together with, for the first time, the corresponding Raman and infrared spectra of solid K2(13)C2O4 x H2O. Raman spectra of aqueous solutions of both isotopomers are also reported. In the solid state the oxalate anion is planar with D2h symmetry in this salt, whereas in aqueous solution the Raman spectra of the anion are best interpreted on the basis of D2d symmetry. The Raman spectra of solid (NH4)2(12)C2O4 x H2O and (NH4)2(13)C2O4 x H2O, in which the oxalate anion is twisted from planarity by 28 degrees about the CC bond, have also been recorded. Several reassignments have been made. The harmonic force field for the oxalate anion in the D2h, D2 and D2d geometries has been determined in part, and approximate values of key valence force constants determined. All the observed band wavenumbers and 12C/13C isotopic shifts are well reproduced by the force fields. The potential energy distribution of the totally symmetric normal modes of planar oxalate indicates that each mode consists of extensively mixed symmetry corrdinates and that the labels previously used for the bands seen here at 475 and 879 cm(-1) would better be described as v(CC) and deltaS(CO2), respectively, putting them in the same wavenumber order as v(NN) and deltaS(NO2) for the isoelectronic and isostructural molecule N2O4. The stretching force constants of N2O4 and planar C2O4(2-) are established to be in the order f(NN) < f(CC) and f(NO) > f(CO), consistent with the known relative bond lengths.     

New compounds from tellurocyanide rhenium cluster anions and 3d-transition metal cations coordinated with ethylenediamine

The compounds [Ni(en)(3)](2)[Re(6)Te(8)(CN)(6)].10H(2)O (1), [Ni(NH(3))(4)(en)](2)[Re(6)Te(8)(CN)(6)].2H(2)O (2), [Ni(NH(3))(2)(en)(2)][(Ni(en)(2))(3)(Re(4)Te(4)(CN)(12))(2)].38H(2)O (3), [Co(NH(3))(2)(en)(2)](2)[(Co(en)(2))Re(6)Te(8)(CN)(6)]Cl(2).H(2)O (4),and [(Zn(H(2)O)(en)(2))(Zn(en)(2))Re(6)Te(8)(CN)(6)].3H(2)O (5) (en = ethylenediamine) have been synthesized and characterized. Compounds 1, 4, and 5 have been synthesized by the diffusion of an aqueous (for 1 and 5) or an ammonia (for 4) solution of Cs(4)[Re(6)Te(8)(CN)(6)].2H(2)O into a glycerol solution of NiCl(2).6H(2)O (for 1), CoCl(2).6H(2)O (for 4), or ZnCl(2) (for 5). Compounds 2 and 3 have been synthesized by the reaction of an aqueous solution of Cs(4)[Re(6)Te(8)(CN)(6)].2H(2)O (for 2) or K(4)[Re(4)Te(4)(CN)(12)].5H(2)O (for 3) with an ammonia solution of Ni(en)(2)Cl(2). Compounds 1 and 2 are ionic whereas compounds 4 and 5 are one-dimensional polymers. Compound 3, a two-dimensional polymer, possesses hexagonal shaped channels of approximate diameter 10-12 A. Because the framework of compound 3 is robust, it is an attractive host for guest molecules of appropriate size and shape. The potential "guest" volume is about 37% of the unit cell volume.     

Structures of vanadium(III)-ethylenediamine-N,N'-diacetato-N,N'-di-3-propionato complexes. Critical role of pπ-dπ donation in determining the coordination number

Li[V(eddadp)]·3H(2)O (1a) and Cs[V(eddadp)]·2H(2)O (1b) were characterized by X-ray crystallography. 1a crystallizes in the monoclinic space group Cc with a = 11.467(7) ?, b = 13.398(8) ?, c = 12.529(8) ?, β = 114.85(4)°; V = 1746.7(2) ?(3), and Z = 4; 1b crystallizes in the monoclinic space group P2(1)/n with a = 10.265(5) ?, b = 11.673(6) ?, c = 15.507(8) ?, β = 104.29(2)°, V = 1800.6(2) ?(3), and Z = 4. The solution structure of 1 has been ascertained to be predominantly six-coordinated with a hexadentate eddadp which is based on a comparison of the electronic and Raman spectra of aqueous solutions of 1 with those in the solid state.     

硫酸铯/乙醇双水相体系的相平衡

采用自制的相平衡研究装置，测定了硫酸铯/乙醇双水相体系在0、10、20和40 ℃四个温度下的等温平衡溶解度，并且获得了醇相溶液和水相溶液的折光率数据，发现温度对该体系的液-液和固-液相平衡均没有显著影响.利用“湿渣结线法”确定出四个温度下平衡固相均为无水盐，同时给出了该体系的完整相图，在相图中观察到五个相区，为该体系的进一步应用研究提供了参考数据.     

Reactivity of polyoxoniobates in acidic solution: controllable assembly and disassembly based on niobium-substituted germanotungstates

The reactivity of polyoxoniobates has been studied in acidic solution by grafting niobium onto trivacant Keggin-type germanotungstates. Four niobium-containing compounds were obtained in the course of this study. Cs(6.5)K(0.5)[GeW(9)(NbO(2))(3)O(37)]·6H(2)O (Cs(6.5)K(0.5)-1) synthesized by the reaction of K(7)H[Nb(6)O(19)] and A-α-Na(10)[GeW(9)0(34)] in H(2)O(2) solution is a tris(peroxoniobium)-substituted A-α-GeW(9) derivative. Cs(6.5)K(0.5)[GeW(9)Nb(3)O(40)]·10H(2)O (Cs(6.5)K(0.5)-2) is a peroxo-free compound obtained by eliminating the peroxo groups in 1. Monomers 1 and 2 as precursors can each afford two nanoscale POMs, dimer Cs(5)[H(15)Ge(2)W(18)Nb(8)O(88)]·18H(2)O (Cs(5)-3) and tetramer Cs(8)K(3)H(9)[Ge(4)W(36)Nb(16)O(166)]·27H(2)O (Cs(8)K(3)H(9)-4), through the formation of Nb-O-Nb bridges. Disassembly through the cleavage of Nb-O-Nb bonds from 4 to 2 and 1 was achieved by controlling the pH and by adding H(2)O(2), respectively. The transition from 1 to 2 can be achieved by simply adding H(2)O(2) to a solution of 1. All four compounds were characterized in the solid state by elemental analysis, infrared spectroscopy, thermogravimetry, and single-crystal X-ray diffraction. (183)W NMR analysis proved that the solid-state structures of polyanions 1-4 were retained after dissolution. Disassembly from 4 to 1 and 2 in solution was observed by (183)W NMR spectroscopy. The UV/Vis spectra of 1 at different pH confirmed that it is stable in the pH range of 0.1-14.0 at room temperature.