The Crystal Structure of Symplesite

Since the discovery of symplesite mineral in the late 19th century, a number of structural studies were performed. The crystal symmetry of this mineral was debated to be either monoclinic or triclinic. Even though this debate has ended, agreeing on the triclinic symmetry, no detailed crystal structure was reported so far. In the present contribution, we report on the crystal structure of symplesite. The crystal structure was solved and refined from high‐resolution laboratory X‐ray powder diffraction data, collected on a natural sample. Symplesite is shown to be isostructural to metavivianite (and possibly to ferrostrunzite).     

雷酚萜醇的结构研究

雷酚萜醇属雷公藤二萜类化合物。雷公藤(Tripterygium wilfordii Hook f)系卫矛科(Celastraceae)雷公藤属植物。民间用于治疗风湿病、抗炎、抗肿瘤及抑制免疫系统等。     

The Crystal Structure of Isosteviol

The title compound was prepared and its crystal structure was determined using X-ray crystallographic method. The crystal is orthorhombic, space group is P212121 with a= 1. 1114(2) nm, b=1.7677(3) nm, c=1.8312(3) nm; Z=8. The geometric structure and conformation of the title compound obtained by MMX molecular mechanics calculation are in agreement with those obtained from X-ray determination.     

The Crystal Structure of Enniatin B

The X-ray crystal structure of enniatin B (trigonal (hexagonal axes), a = 14.626 Å, c = 16.309 Å, space group R3) is described and the conformation compared to results of other investigations.     

5-[(3,5-二溴-2-吡啶)偶氮]-2,4-二氨基甲苯的晶体结构

5-[(3,5-二溴-2-吡啶)偶氮]-2,4-二氨基甲苯对铜和钴是高灵敏度和高选择性试剂,其单晶系P2₁/n空间群,晶胞参数α=11.477(5)Å、b=15.642(6)Å、c=8.311(4)Å、β=110.54(4)°,每个晶胞中有4个分子。     

二乙三胺五乙酸锑的晶体结构

二乙三胺五乙酸锑的分子式为C_(14)H_(20)O_(10)N_3Sb,M_r=609.65,属单斜晶系,空间群为Cm,晶胞参数a=7.317A,b=19.951A,c=6.899A;β=116.24°,V=904.46A~3,Z=2。晶体结构用重原子法与直接法解出,结构经全矩阵最小乘法修正后偏离因子R=0.031和Rω=0.0314。结构表明分子中的Sb原子以sp~3d~3杂化的六个轨函与二乙三胺五乙酸中的三个氧原子和三个氮原子相配合,它们与Sb的孤对电子分别占据五角双锥各个角顶的位置。     

The Crystal and Molecular Structure of Fargesin

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The Crystal Structure of a New Borogermanosilicate

The structure of Nd₃BGe_1.08Si_0.92O₁₀ has been determined by a single crystal investigation. The orthorhombic cell parameters are a = 9.845(1) Å, b = 7.146(1) Å, and c = 23.382(2) Å. The space group is Pbca (Z = 8). Out of 10,833 measured reflections, 3,099 independent reflections (I > 3σ(I)) have been used in the refinement of the structure. The R factor value is 0.026 (wR = 0.023). The neodymium ions occupy three different sites with eight or nine oxygen bonds in the lattice. The germanium and silicon ions are located in a distorted tetrahedral environment. The boron atom coordination is triangular with a shorter B-O distance of 1.384 Å.     

The Crystal Structure of Biphenyltetracarboxylic Dianhydride Isomers

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The Crystal Structure of MnF3 Revisited

We correct the crystal structure of MnF₃, of which the space group was reported as monoclinic C2/c (no. 15) with a = 8.9202, b = 5.0472, c = 13.4748 Å, β = 92.64°, V = 606.02 ų, Z = 12, mS48, T not given, likely 298 K. In the structure model proposed here, we use a unit cell of one third of the former volume. The ruby red crystals of MnF₃ were synthesized by a high-pressure/high-temperature method, where MnF₄ was used as a starting material. As determined on a single crystal, MnF₃ crystallizes in the monoclinic space group I2/a (no. 15) with a = 5.4964(11), b = 5.0084(10), c = 7.2411(14) Å, β = 93.00(3)°, V = 199.06(7) ų, Z = 4, mS16, T = 183(2) K. The crystal structure of MnF₃ is related by a direct group-subgroup transition to the VF₃ structure-type. We performed quantum chemical calculations on the crystal structure to allow the assignment of bands of the obtained vibrational spectra.     

The Crystal Structure of Four Phosphorus-Containing Polyoxamacrocycles

Abstract

The crystal structures of four phosphorus-containing polyoxamacrocycles 2,4, 6,11,13-Pentachloro-dibenzo[d,g][1,3,9,2]trioxaphosphacycloundecan-2-thione (1),2,4,9,14, 16-Pentachloro-dibenzo[g,j][1,3,6,12,2]tetraoxaphosphacyclotetra-decan-2-thione (2), 2,4, 10,16,18-Pentachloro-dibenzo[h,k][1,3,7,12,2]tetraoxa-phosphacyclohexadecan-2-thione (3) and 2,4,6,12,14,18,20,28,30—Nona-chloro-tetrabenzo[d,g,p,s] [1,3,9,13,15,21,2,14]hexaoxa diphosphacyclotetracosan-2,14-dithione (4) have been determined by X-ray diffraction. The result shows that compound 4 has a center of symmetry, and compounds 1, 2, and 3 have no elements of symmetry. The molecules of compounds 2 and 4 form inclusion complex with neutral molecule guest (CHCl₃) which is outside of the phosphorus-containing macrocycle in the ratio of 1:1, and compounds 1 and 3 do not form inclusion complexes with CHCl₃. The result obtained in this paper lays a foundation for further research on the complexing properties of phosphorus-containing polyoxamacrocycles.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text, figures, and tables.]     

2—肉桂酰噻吩的晶体结构

标题化合物进行了X—射线分析。该化合物晶体属正交晶系,Pbcm空间群,a=10.984(3),b=11.808(3),c=17.224(4)A,Z=8。1035个Ⅰ≥2σ(Ⅰ)的反射数据用于结构确定和修正,最终R=0.059。噻吩基平面与羰基平面的二面角略小于苯乙烯基平面与羰基平面的二面角,表明噻吩基与羰基的共轭倾向比苯乙烯基与羰基的略强,或者近乎相当。这一结果支持了噻吩基的端基当量为3的观点。     

冬凌草甲素乙酰衍生物的晶体结构

冬凌草甲素是从抗癌中草药冬凌草中提取的一种有效成分。它的乙酰衍生物的晶体结构和分子结构已由X—射线衍射法中直接法解出,R因子被修正到0.067。其晶体属单斜晶系,空问群为P2_1,晶胞参数是:a=8.923(3),b=6.551(2),c=20.102(3),β=99.77(2)°晶胞中含有两个C_(22)H_(30)O_7分子和两个乙醇(溶剂)分子。 晶体结构分析表明,分子中含有部分共轭的α—亚甲基环戊酮的五员环。其内角均分别地远小于各自碳原子SP~2或SP~3杂化所要求的数值,而含有较大的内应力。     

The Crystal Structure of Triuranyl Diphosphate Tetrahydrate

The hydrated neutral uranyl phosphate, (UO₂)₃(PO₄)₂(H₂O)₄, was synthesized by hydrothermal methods. Intensity data were collected using MoKα radiation and a CCD-based area detector. The crystal structure was solved by direct methods and refined by full-matrix least-squares techniques to agreement indices wR₂=0.116 for all data, and R1=0.040, calculated for the 2764 unique observed reflections (∣F_o∣≥4σ_F). The compound is orthorhombic, space group Pnma, Z=4, a=7.063(1) Å, b=17.022(3) Å, c=13.172(3) Å, V=1583.5(5) ų. The structure consists of sheets of phosphate tetrahedra and uranyl pentagonal bipyramids, with composition [(UO₂)(PO₄)]⁻ and the uranophane sheet anion topology. The sheets are connected by a uranyl pentagonal bipyramid in the interlayer that shares corners with a phosphate tetrahedron on each of two adjacent sheets, resulting in an open framework with isolated H₂O groups in the larger cavities of the structure.     

The Crystal Structure of Dimethylamino Titanium Trichloride

Green crystals of Me₂NTiCl₃ associate to a chain polymer via four Ti‐Cl‐Ti bonds and generation of hexacoordinated Ti atoms. Like Et₂NTiCl₃ its amino group is not involved into forming Ti‐N‐Ti bridges. This is due to a short Ti‐N bond to the planar coordinated N atom of the Me₂N group.