基于H3PW12O40·xH2O和3，5-二氨基-1，2，4-三氮唑的POMOF的合成、表征及催化氧化碘离子性能

采用水热法合成了一例结构新颖且罕见的Keggin型多金属氧酸盐基金属有机骨架化合物，即[Cu₄(3，5 - dtrz)₄][PW^Ⅵ₉W^Ⅴ₃O₃₉]·H₂O (1)，其中3，5-dtrz=3，5-二氨基-1，2，4-三氮唑，并通过单晶X射线衍射、傅里叶变换红外光谱、热重分析、粉末X射线衍射和元素分析进行了表征。单晶X射线衍射分析表明：化合物1属于单斜晶系，空间群为C2/c，不对称结构包含2个Cu⁺、2个3，5-datrz配体、0.5个Keggin型磷钨酸阴离子和1个水分子，除结晶水外各组分之间通过共价键连接成Keggin型多金属氧酸盐基金属有机骨架化合物。以化合物1为非均相催化剂，在温度为55℃时催化H₂O₂氧化碘离子反应。结果表明，1催化下的碘单质生成速率为6.11×10^-7 mol·L-1·s^-1，且重复使用次数达到6次时转化率仍能高达99.6%。     

异核Ln(Na)-MOFs(Ln=Tb、Dy、Ho)的晶体结构及对乙醛、Fe3+、Cr2O72-的荧光传感和邻苯二酚的电化学传感

在溶剂热条件下合成了3个新型三维微孔同构异核金属有机骨架Ln （Na）-MOFs：{[LnNa （BDT）（H₂O）₃]·2H₂O}_n（Ln=Tb （1）、Dy （2）、Ho （3）,H₄BDT=3,5-二（3'',5''-二羧基苯基）-1H-1,2,4-三唑）,并通过单晶X射线衍射、元素分析、热重分析和粉末X射线衍射技术对其进行表征。结构分析表明,Ln （Na）-MOFs是具有相同的异核双金属单元的三维骨架结构。荧光研究表明,Tb （Na）-MOF （1）可以荧光传感检测水中Fe³⁺、Cr₂O₇^2-以及乙醛分子,具有较高的灵敏度和选择性,也可用于水中邻苯二酚的电化学检测。     

基于3，5-二硝基苯甲酸和2，2'-联吡啶的Cu(Ⅱ)、Zn(Ⅱ)配合物的合成及晶体结构

以3,5-二硝基苯甲酸(3,5-Hdnbc)和2,2'-联吡啶(2,2'-bipy)为配体,与Zn²⁺和Cu²⁺反应,得到了4个配合物[Zn(3,5-dnbc)₂(2,2'-bipy)(H₂O)]·(3,5-Hdnbc)(1),[Cu(3,5-dnbc)₂(2,2'-bipy)(H₂O)](2),[Cu(2,2'-bipy)₂(3,5-dnbc)](NO₃)·2(3,5-Hdnbc)(3),和[Cu(2,2'-bipy)₂Cl](3,5-dnbc)·(3,5-Hdnbc)(4)。用元素分析、红外光谱对其进行了表征,并用单晶X-射线衍射测定了配合物的晶体结构;对配合物1和2进行了热重分析。4个配合物均为单核分子。配合物1中,Zn²⁺离子是五配位的三角双锥结构;配合物2中,Cu²⁺离子是五配位的变形四方锥结构;配合物3和4中,Cu²⁺离子均是五配位的三角双锥结构;配合物中存在氢键和π-π堆积等弱的分子间作用力。     

基于3，4'，5-联苯三羧酸构筑的钕配合物的合成、结构、荧光、光催化及磁性质

采用NdCl₃·6H₂O和3,4'',5-联苯三羧酸（H₃bpt）为原料在DMF/H₂O混合溶剂热条件下合成得到一个三维钕配合物{[Nd （bpt）（DMF）（H₂O）]·2H₂O}_n（1）,并通过红外光谱、元素分析、单晶及粉末X射线衍射表征了配合物1的结构。单晶衍射结果表明,配合物1具有（5,5）-连接的三维结构,拓扑符号为（4⁴·6³·8³）（4⁸ 6²）。此外,对配合物1的热稳定性、荧光性质、光催化降解染料及磁性质进行了详细研究。     

多功能Zn（Ⅱ）金属有机骨架荧光传感器检测苯甲醛、四环素、2，4，6-三硝基苯甲酸、氟啶胺、Cr2O72-和Fe3+

成功制备了新型Zn（Ⅱ）金属有机骨架(MOF)[Zn₂(Hdepa)(dya)₂]_n (1)(H₅depa=2,2'',3,4'',5-二苯醚五羧酸,dya=2,2''-二吡啶胺)。单晶X射线衍射分析表明MOF 1由2个Zn²⁺离子与1个Hdepa^4-离子和2个dya分子连接组成,通过氢键形成三维骨架。用粉末X射线衍射和IR表征了配合物1的相纯度。值得注意的是,配合物1具有优异的荧光特性和热稳定性,1的高灵敏度和选择性使其能够作为荧光传感器检测苯甲醛(BZH)、四环素(TC)、2,4,6-三硝基苯酚(TNP)、氟啶胺(Flu)、Cr₂O₇^2-和Fe³⁺。此外,通过荧光寿命分析了Fe³⁺、TC、BZH对MOF 1的荧光的猝灭过程,通过能量转移研究了Fe³⁺、Cr₂O₇^2-、TNP、TC、BZH和Flu的荧光猝灭机理。     

基于多金属氧酸盐和多壁碳纳米管的双酚A电化学传感器的构建与性质

选择含N配体（L=1,3-双（1-咪唑）丙烷）与磷钼酸（H₃PMo₁₂O₄₀）水热合成了一个新的无机-有机杂化化合物（H₂L）₂（HL）₂L （PMo₁₂O₄₀）₂·2H₂O （PMo₁₂）。通过红外、热重、X射线光电子能谱、X射线粉末衍射和单晶衍射等对该化合物进行了表征。X射线单晶衍射表明该化合物为3D结构。将该化合物和多壁碳纳米管修饰在玻碳电极上构造了一种双酚A电化学传感器并对其传感性能进行研究。研究表明,在1~20 μmol·L^-1范围内,检出限为0.5 μmol·L^-1（S/N=3）,并且该传感器具有良好的抗干扰和稳定性。     

由4-甲基-1，2，3-噻二唑-5-甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以4-甲基-1,2,3-噻二唑-5-甲酸（C₄H₄N₂O₂S, HL）分别与硫酸钴（CoSO₄·7H₂O）、氯化铜（CuCl₂·2H₂O）、硝酸银（AgNO₃）反应合成了3个配合物[Co（L）₂（H₂O）₄] ·2H₂O （1）、[CuNa（L）₃] _n （2）和[AgL] _n （3）,用元素分析、红外光谱、热重分析进行表征,用单晶X射线衍射测定了产物的结构。配合物1属于三斜晶系,空间群P1,Co²⁺的配位数为6,形成一个略为拉长的CoN₂O₄八面体,与理想的正八面体非常接近。配合物2属于三斜晶系,空间群P1。Cu²⁺离子的配位数为4,构成变形的平面四边形结构,Na⁺离子的配位数为6,构成一个略微变形的八面体结构,最终形成三维网状结构。配合物3属于单斜晶系,空间群P2₁/c,银离子为三配位,构成变形的平面三角形构型,具有二维网状结构。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱。     

三角柔性多羧酸金属有机骨架化合物的合成、结构及荧光性质

以柔性1,3,5-三（4-羧酸苯氧基）苯（H₃TCPB）为配体,以4,4''-联吡啶（4,4''-BPY）为辅助配体,在溶剂热条件下合成了2个新颖的分别具有三核锌簇和三核钴簇的金属有机骨架化合物：{[Zn₃（TCPB）₂（4,4''-BPY）]·DMF·3H₂O}_n（1）和{[Co_1.5（TCPB）（DMF）（H₂O）]·DMF}_n（2）,通过单晶X射线衍射,红外光谱,元素分析,热重分析和粉末X射线衍射对其结构进行了表征。单晶X射线衍射分析表明化合物1属于三斜晶系,P1空间群,表现出三维（3,8）连接的网状结构,拓扑符号为：{4³}₂·{4⁶·6¹⁸·8⁴}·{6};化合物2也属于三斜晶系,P1空间群,为二维（3,6）连接的网络层状结构,拓扑符号为：{4³}₄·{4⁶·6¹⁸·8⁴}。此外,荧光性质研究表明固态化合物¹在室温条件下发射出源于TCPB^3-和4,4''-BPY配体的淡蓝色荧光,而化合物2在相似的条件下没有荧光发射。     

基于4-氨基-1,2,4-三唑和多金属氧酸盐为杂化配体的CuⅡ和CuⅠ配合物的水热合成及光催化性能

在水热条件下,制备了2个基于多金属氧酸盐（POM）的Cu^Ⅱ和Cu^Ⅰ新型杂化配合物材料,即[Cu₂（4-NH₂-trz）₄（Mo₈O₂₆）（H₂O）₄]·5H₂O（1）和[Cu₄（4-NH₂-trz）₄Mo₈O₂₆]（2）（4-NH₂-trz=4-氨基-1,2,4-三唑）。通过单晶X射线衍射、傅里叶变换红外光谱和粉末X射线衍射分析确定了它们的结构。在配合物1中,4-氨基-1,2,4-三唑双齿配体连接2个相邻的Cu^Ⅱ中心形成双核结构单元,这些双核结构单元进一步通过Mo₈O₂₆^4-连接形成一维（1D）的杂化配位结构。在配合物2中,4-氨基-1,2,4-三唑双齿配体连接相邻Cu^Ⅰ中心构筑了独特的[Cu₄（4-NH₂-trz）₄]_n一维螺旋链,这些左手和右手的一维螺旋链再通过（β-Mo₈O₂₆）^4-连接形成2D杂化骨架。光催化实验研究表明,样品1和样品2对于不同有机染料（亚甲基蓝（MB）、罗丹明B（RhB）和甲基橙（MO））具有很好的光催化降解能力。     

基于4-氨基-1,2,4-三唑和多金属氧酸盐为杂化配体的CuⅡ和CuⅠ配合物的水热合成及光催化性能

在水热条件下,制备了2个基于多金属氧酸盐（POM）的Cu^Ⅱ和Cu^Ⅰ新型杂化配合物材料,即[Cu₂（4-NH₂-trz）₄（Mo₈O₂₆）（H₂O）₄]·5H₂O（1）和[Cu₄（4-NH₂-trz）₄Mo₈O₂₆]（2）（4-NH₂-trz=4-氨基-1,2,4-三唑）。通过单晶X射线衍射、傅里叶变换红外光谱和粉末X射线衍射分析确定了它们的结构。在配合物1中,4-氨基-1,2,4-三唑双齿配体连接2个相邻的Cu^Ⅱ中心形成双核结构单元,这些双核结构单元进一步通过Mo₈O₂₆^4-连接形成一维（1D）的杂化配位结构。在配合物2中,4-氨基-1,2,4-三唑双齿配体连接相邻Cu^Ⅰ中心构筑了独特的[Cu₄（4-NH₂-trz）₄]_n一维螺旋链,这些左手和右手的一维螺旋链再通过（β-Mo₈O₂₆）^4-连接形成2D杂化骨架。光催化实验研究表明,样品1和样品2对于不同有机染料（亚甲基蓝（MB）、罗丹明B（RhB）和甲基橙（MO））具有很好的光催化降解能力。     

Syntheses, structures, optical properties, and theoretical calculations of Cs2Bi2ZnS5, Cs2Bi2CdS5, and Cs2Bi2MnS5

Three new compounds, Cs₂Bi₂ZnS₅, Cs₂Bi₂CdS₅, and Cs₂Bi₂MnS₅, have been synthesized from the respective elements and a reactive flux Cs₂S₃ at 973 K. The compounds are isostructural and crystallize in a new structure type in space group Pnma of the orthorhombic system with four formula units in cells of dimensions at 153 K of a=15.763(3), b=4.0965(9), c=18.197(4) Å, V=1175.0(4) Å³ for Cs₂Bi₂ZnS₅; a=15.817(2), b=4.1782(6), c=18.473(3)  Å, V=1220.8(3)  ų for Cs₂Bi₂CdS₅; and a=15.830(2), b=4.1515(5), c=18.372(2) Å, V=1207.4(2) Å³ for Cs₂Bi₂MnS₅. The structure is composed of two-dimensional _∞²[Bi₂MS₅²⁻] (M=Zn, Cd, Mn) layers that stack perpendicular to the [100] axis and are separated by Cs⁺ cations. The layers consist of edge-sharing _∞¹[Bi₂S₆⁶⁻] and _∞¹[MS₃⁴⁻] chains built from BiS₆ octahedral and MS₄ tetrahedral units. Two crystallographically unique Cs atoms are coordinated to S atoms in octahedral and monocapped trigonal prismatic environments. The structure of Cs₂Bi₂MS₅, is related to that of Na₂ZrCu₂S₄ and those of the AMM′Q₃ materials (A=alkali metal, M=rare-earth or Group 4 element, M′= Group 11 or 12 element, Q=chalcogen). First-principles theoretical calculations indicate that Cs₂Bi₂ZnS₅ and Cs₂Bi₂CdS₅ are semiconductors with indirect band gaps of 1.85 and 1.75 eV, respectively. The experimental band gap for Cs₂Bi₂CdS₅ is ≈1.7 eV, as derived from its optical absorption spectrum.     

Theoretical study of polyoxide clusters B20O30, Al20O30, V20O50, Si20O30H20, and Si20O30F20

The structural, electronic, and vibrational characteristics and energies of the isolated polyoxide clusters B₂₀O₃₀, Al₂₀O₃₀, V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀ and their complexes with the H⁻ ion and ammonia complexes Al₂₀O₃₀ · nNH₃ have been calculated by the density functional theory B3LYP method with different basis sets. The computation results show that the symmetric closo structure I _h with oxygen bridges located above the centers of the faces of an empty [M₂₀] dodecahedron is more favorable for V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀. For B₂₀O₃₀, the cage closo isomer is also more favorable than the other isomers, but its structure is severely distorted as compared to a dodecahedron and has a symmetry close to C ₃ . For Al₂₀O₃₀, the I _h structure corresponds to a high-lying local minimum of the potential energy surface. For Al₂₀O₃₀, a set of unusual puckshaped isomers of symmetry C _i , with different numbers of four-coordinate atoms ^IVAl and three-coordinate atoms ^IIIO, was localized; these structures are more than 90 kcal/mol more favorable than the dodecahedron I _h . The most favorable isomer of Al₂₀O₃₀ contains twelve four-coordinate atoms ^IVAl and four five-coordinate atoms ^VAl. The energies of dissociation of the most favorable M₂₀O₃₀ clusters into the M₂O₃ (C _2v ) and M₄O₆ (T _d ) fragments and, in the case of Al₂₀O₃₀, also into the Al₈O₁₂ (O _h ) and Al₁₂O₁₈ (D _3d ) fragments, have been estimated. The conclusion has been drawn that these clusters can, in principle, exist and can be experimentally detected in the isolated state. Analogous calculations have been performed for ammonia complexes Al₂₀O₃₀ · nNH₃ with n varying from 1 to 20. The effect of solvation on the relative stability of the dodecahedral and puckshaped isomers of the Al₂₀O₃₀ cluster is observed. The isomers with ammonia molecules in their first coordination sphere become much closer to one another on the energy scale; however, the dodecahedron remains a considerably less favorable intermediate. Original Russian Text ? O.P. Charkin, N.M. Klimenko, D.O. Charkin, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 624–635.     

Ab Initio calculation of molecular, thermodynamic, and kinetic parameters of CF, CF2, CF3, and C2F5 radicals and CF4, CF3I, C2F4, and C2F6 molecules in gas

Enthalpies of formation of ground states of the gaseous particles CF, CF₂, C₂F₅, CF₄, CF₃I, C₂F₄, and C₂F₆ were calculated by ab initio method in the CCSD(T) approximation with extrapolation to the full basis and regard to the correlation energy. Their equilibrium geometrics, frequencies of normal vibrations, and other values were found by the B3LYP/aug-cc-pvdz method, from which thermodynamic functions within the range of 0–6000 K were calculated. Equilibrium constants were calculated from these functions, and then the information on the rate constants in the limit of high pressures was obtained.     

Ionization gauge sensitivities of N2, O2, N2O, NO, NO2, NH3, CClF3 and CH3OH

A Bayard-Alpert (BA) gauge was used to determine apparent relative sensitivites S_rel,X for O₂, N₂O, NO, NO₂, NH₃, CClF₃ and CH₃OH from gauge calibration measurements in the range 1.3×10^–1 Pap1.3·10^–3Pa. Nitrogen was used as a calibration standard.     

Zur Trennung von H2, O2, N2, NO, CO, N2O, CO2, C2H6, C2H4, C2H2, NO2(N2O4) und Feuchtigkeit

Ohne Zusammenfassung     

Lithium intercalation into PbNb2S5, PbNbS3, SnNb2Se5, BiVS3, SnVSe3, and PbNb2Se5 misfit layer chalcogenides

The intercalation of lithium into various misfit layer chalcogenides of two different stoichiometries was performed by using n-butyl lithium on powders. The reaction was found to proceed topochemically, and a greater expansion in the c direction and higher lithium contents were observed in the lithiated phases with “MM′₂X₅” approximate stoichiometries compared to “MM′X₃” stoichiometries. This behaviour difference is assigned to the different stacking sequence of the slices of the two sublattices formed by double layers of MX and sandwiches of M′X₂. Lattice distortions are induced during lithiation, leading to changes in the relative orientation of MS-type bilayers and to complete amorphization after long reaction times. The synthesis and partial characterization of a new misfit layer selenide of nominal composition “PbNb₂Se₅” is also reported. The value of the c-dimension (c = 37.3₇ Å) suggests a stacking sequence PbSe---NbSe₂---NbSe₂---PbSe---NbSe₂---NbSe₂, etc. This material becomes highly unstable on lithium intercalation and decomposes to its constituents after a few hours of lithiation.     

Synthesis and crystal structures of Nd6Pt13In22, Sm6Pt12.30In22.70, and Gd6Pt12.48In22.52

The rare earth-platinum-indides Nd₆Pt₁₃In₂₂, Sm₆Pt_12.30In_22.70, and Gd₆Pt_12.48In_22.52 were synthesized from the elements by arc-melting of the components. Single crystals were grown using special annealing sequences. The three indides were investigated by X-ray powder and single crystal diffraction: Tb₆Pt₁₂In₂₃ type, C2/m, Z=2, a=2811.9(6), b=441.60(9), , β=112.10(3)°, wR₂=0.0629, 3645 F² values, 126 variables for Nd₆Pt₁₃In₂₂, a=2821.9(6), b=443.06(9), , β=112.39(3)°, wR₂=0.0543, 3679 F² values, 127 variables for Sm₆Pt_12.30In_22.70, and a=2818.5(6), b=439.90(9), , β=112.29(3)°, wR₂=0.0778, 3938 F² values, 127 variables for Gd₆Pt_12.48In_22.52. Most platinum atoms in these structures have a distorted trigonal prismatic coordination by rare earth metal and indium atoms. Together, the platinum and indium atoms build up a complex three-dimensional [Pt_12+xIn_23−x] polyanionic network in which the rare earth metal atoms fill distorted pentagonal and hexagonal channels. The 2c Wyckoff site in these structures plays a peculiar role. This site is occupied by indium in the prototype Tb₆Pt₁₂In₂₃, while platinum atoms fill the 2c site in Nd₆Pt₁₃In₂₂, leading to a linear Pt₃ chain with Pt-Pt distances of 275 pm. The crystals with samarium and gadolinium as rare earth metal component show mixed Pt/In occupancies.     

Singlet-triplet energy separation in divalent seven-membered cyclic conjugated compounds C6H6C, C6H6Si, C6H6Ge, C6H6Sn, and C6H6Pb

The electronic and thermal energy differences, ΔE(t-s); enthalpy differences, ΔH(t-s); and free energy differences between the singlet and triplet states, ΔG(t-s), were calculated for C₆H₆C, C₆H₆Si, C₆H₆Ge, C₆H₆Sn, and C₆H₆Pb at the B3LYP/6-311++G (3df, 2p) level. The singlet-triplet splitting, G _s-t, of C₆H₆C, C₆H₆Si, C₆H₆Ge, C₆H₆Sn, and C₆H₆Pb generally increased from C₆H₆C toward C₆H₆Pb. The most stable tautomers and conformers were suggested for the singlet and triplet states of C₆H₆M (M = C, Si, Ge, Sn and Pb). The geometrical parameters were calculated and discussed. The text was submitted by the authors in English.     

Theoretical study of polyoxide clusters Sc20O30, P20O50, Ti20O30F20, and V20O30F20

The structural, electronic, and vibrational characteristics and energies of the isolated polyoxide clusters Sc₂₀O₃₀, P₂₀O₅₀, Ti₂₀O₃₀F₂₀, and V₂₀O₃₀F₂₀ and ammonia complexes Sc₂₀O₃₀ · nNH₃ were calculated by the density functional theory B3LYP method with several basis sets. The computation results show that a fullerene-like closo structure I _h with oxygen bridges located above the midpoints of the edges of an empty [M₂₀] dodecahedron is preferable for the Ti₂₀O₃₀F₂₀ and V₂₀O₃₀F₂₀ clusters with four-coordinate metal atoms protected by the outer M-F bonds. This structure with a cage diameter of ∼1 nm and the diameter of nearly planar decagonal faces (windows) of ∼0.5 nm is stable to dissociation into fragments and to strong geometric distortions and retains its closo shape when molecules like NH₃ and anions like H⁻ are attached to the cage. An analogous closo structure is favorable for the P₂₀O₅₀ cluster; however, in this structure, the [P₂₀] cage is severely distorted and all 12 windows are strongly corrugated. For Sc₂₀O₃₀, the I _h dodecahedron with bare three-coordinate Sc atoms corresponds to a local minimum of the potential energy surface, which is 170–200 kcal/mol less favorable than compact puck-shaped isomers in which four- and five-coordinate metal atoms and three- and four-coordinate oxygen atom prevail. “Solvation” of the dodecahedral and puck-shaped Sc₂₀O₃₀ isomers by ammonia molecules strongly decreases the energy gap between the isomers; however, the dodecahedron I _h in all cases remains a high-lying intermediate. According to calculations, most polyoxides under consideration have a high electron affinity (comparable with or higher than that of fullerenes) and is able to add three to five or more alkali-metal atoms to form radical salts in which clusters are in the state of polyanions. Because of large sizes of the [M₂₀] cages and their windows, the interior of the cage (as distinct from fullerenes) can accommodate a considerable number of atoms and several small molecules. The V₂₀O₃₀F₂₀ cluster has 20 unpaired electrons and can be treated as a molecular magnet. The properties of the [M₂₀] cages depend only slightly on the outer substituents. It is suggested that the pattern will be retained upon the substitution of OH groups for the F atoms and that the hydroxo-substituted clusters can bind to each other through hydrogen bridges and serve as building blocks for self-assembly into ordered nanometer and crystalline structures of various dimensions. Original Russian Text ? O.P. Charkin, N.M. Klimenko, D.O. Charkin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 775–785.     

Synthesis and crystal chemistry of BaNd2Ti3O10, BaNd2Ti5O14, and Nd4Ti9O24

Two new ternary compounds BaNd₂Ti₃O₁₀ (1:1:3) and BaNd₂Ti₅O₁₄ (1:1:5) have been identified in the BaONd₂O₃TiO₂ system. Single crystals of the compounds were grown and unit cell dimensions and space group symmetry were determined. BaNd₂Ti₃O₁₀ is orthorhombic with a = 3.8655 ± 0.0003, b = 28.156 ± 0.003 and c = 7.6221 ± 0.0007 Å and possible space groups are Cmcm or Cmc2. The compound melts congruently at 1640 ± 20°C. BaNd₂Ti₅O₁₄ is also orthorhombic with a = 22.346 ± 0.002, b = 12.201 ± 0.001 and c = 3.8404 ± 0.0003 Å and possible space groups are Pbam and Pba2. This compound melts congruently at 1540 ± 20°C. Single crystals of the binary compound Nd₄Ti₉O₂₄ were also grown and found to be orthorhombic with a = 35.289 ± 0.003, b = 13.991 ± 0.001, c = 14.479 ± 0.001 Å, space group Fddd.