The crystal structure of hexabenzoylhexaazaisowurtzitane

The crystal and molecular structure of an interesting cage compound is described. Crystal data: C₄₈H₃₆N₆O₆·(CH₃)₂CO; monoclinic; space group: P2 ₁ /n; a = 14.948(3) Å, b = 15.079(3) Å, c = 19.539(4)Å, = 93.93(3)°, V = 4394(2)ų; and Z = 4.     

The crystal structure of 2-nitroresorcinol

2-Nitroresorcinol is triclinic, space group P; at –100°Ca=7.083(2),b=7.696(2),c=6.607(2) Å, =74.61(2), =77.81(2), =68.64(2)°,V=320.8(2) ų,D _x=1.606(1) g cm^–3,Z=2. The two hydroxyl groups form symmetric intramolecular hydrogen bonds to the nitro group. The molecules pack in stacks held together by - interaction with adjacent molecules in a head-to-tail arrangement.     

The crystal structure of 4-iodoacetophenone azine

4-Iodoacetophenone azine crystallizes in the space group Pbcn with cell parametersa = 34.5187(19), b = 7.2638(4), and c = 6.3736(3) Å. The azine shows a gauche conformation with regard to the N—N bond and the phenyl rings are twisted in a way that leads to the largest possible twist between the benzene rings of each azine. This azine conformation allows for intermolecular arene–arene T-contacts between pairs of benzene rings and these double-T contacts involve only molecules within the same layer. All azines are perfectly colinear within each layer and this results in a quadrilateral kite-shaped arrangement of iodine atoms at the interface of each layer. The iodine-iodine distances within each layer are 4.5 and 5.1 Å, and the three unique angles of the kite-shaped quadrilaterals are 97.1, 76.9, and 88.8°. The iodine atoms in adjacent layers pack such that atoms of one layer fill the square interstices of the next layer. The distances between iodine atoms in adjacent layers are 4.5 and 4.1 Å. The C—I bonds are not orthogonal to the I-planes and the direction of the molecules in adjacent layers causes a deviation of about 40° from colinearity     

The crystal structure of calcium succinate monohydrate

The crystal structure of calcium succinate monohydrate, Ca(C₄H₄O₄)·H₂O, has been determined by single crystal X-ray diffraction. The crystals are monoclinic witha=11.952(2),b=9.691(2),c=11.606(2)Å, =108.81(1)°, space group C2/c,Z=8,V=1272.49 ų,d _m =1.80, andd _c =1.818 Mg m^–3. The structure was refined by full-matrix least-squares techniques toR=0.027,R _w =0.040, for 829 reflections with13(I). Ca is coordinated to seven oxygen atoms, and the coordination polyhedron is best described as a pentagonal bipyramid. One carboxylate group in the succinate ion is bonded to three different Ca ions, forming a four-membered chelate ring with one Ca ion is bonded to three different Ca ions, forming a four-membered chelate ring with one Ca ion and unidentate bridge bonds to two other Ca ions. The other carboxylate group is bonded to two Ca ions through unidentate bonds. The structure is highly polymeric. The general structural features are nearly identical to those of calcium adipate monohydrate.Certain commercial materials and equipment are identified in this paper to specify the experimental procedure. In no instance does such identification imply recommendation or endorsement by the National Institute of Standards and Technology or the ADA Health Foundation or that the material or equipment identified is necessarily the best available for the purpose.     

The molecular and crystal structure of p-methyl-phenyl glyoxylacid-m-trifluoro-anilide

Using X-ray crystal structure analysis of the title compound the positions of all atoms (including all A atoms) were localized in the triclinic unit cell with the parameters a = 14.68₆ Å, b = 7.70₀ Å, c = 7.89₈ Å, α = 122.5°, β = 105.4°, γ = 87.7°, space group P1. The existence of an intramolecular H N … O(1) bridge was inferred, the H-bridge acceptor of which predominantly is the π-electron density of the carbonyl group in agreement with the results of the X-ray crystal structure analysis of p-methyl-phenyl-glyoxyl-acid-p-chloroanilide (HOEHNE , SEIDEL ). Moreover, the existence of H-bridgelike interactions of the two phenyl hydrogen atoms H(6) and H(15) to the carbonyl oxygen O(2) could be proved. These interactions stabilize the conformation of the two phenyl rings in the molecule.     

The x-ray crystal and molecular structure of glechomafuran

The X-ray crystal structure of glechomafuran (1,10,4,5-diepoxy-7,8-furanogermacrane), a natural product obtained from seeds ofSmyrnium olusatrum L., has been determined in order to establish the correct relative configuration of the molecule. Crystals are monoclinic, space groupP2₁ witha=6.785(4),b=12.325(9),c=16.390(6) Å,=97.89(4)°, and four molecules in the unit cell. The two epoxides are found to be ,-attached, and the associated methyl groups are positionedsyn to each other. The furan ring is essentially flat, and shows no evidence of any double bond delocalization.     

The crystal structure of vyuntspakhite: A redetermination

The crystal structure of the mineral vyuntspakhite (Y, TR)₆{Al₂(OH)₃[H_1.48Si_1.88O₇][SiO₄][SiO₃(OH)]}₂(a = 5.7551(11) Å, b = 14.752(3) Å, c = 15.906(4) Å, β = 96.046(4)°, sp. gr. P2₁/n, Z = 2), which had been established earlier in the pseudo-unit cell, is redetermined by X-ray diffraction (R = 0.040, T = 100 K). The redetermination of the structure shows that pronounced pseudotranslation along the axis c′ = c/3 is associated with the fact that Y(TR) atoms are related by a 1/3 translation along the [001] direction. Most of the hydrogen atoms are located. The crystal-chemical function of hydrogen bonds is analyzed. In the unit cell of vyuntspakhite, the cationic layers consisting of edge-sharing (Y,TR) eight-vertex polyhedra alternate along the b axis with mixed anionic layers composed of isolated Si tetrahedra (orthotetrahedra), Si₂O₇ double-tetrahedra (diortho) groups, Al five-vertex polyhedra, and Al₂O₈ double-tetrahedra groups linked by shared vertices and through hydrogen bonding.     

The crystal and molecular structure of 2-S-methylthiouracil

2-S-Methylthiouracil crystallizes in the triclinic space group P with unit cell dimensions a = 5.508(4), b = 7.175(3), c = 8.522(2) Å, = 80.83(2), = 80.43(3), = 76.86(3)°, and Z = 2. The molecule exists in the crystal in the lactam form and is essentially planar. The molecular packing consists of molecules linked in centrosymmetric hydrogen-bonded pairs. The effects of methylation and subsequent metallation on the 2-thiouracil structure are discussed.     

The crystal structure and vibrational spectra of potassium oxathioamidate

The crystal and molecular structure determination of the title compound, K–SO₂NC₂H₂,M _r=143.21, (1) is part of a series of determinations of N-substituted oxathioamidates. The structure has been refined using single-crystal X-ray diffraction data measured at 295 K [MoK-radiation with =0.71073 Å]. The crystals are orthorhombic, space group P_n2la,Z=8, with cell dimensions:a=11.399(2) Å,b=22.131(2) Å,c=4.021(1) Å,V=1014.5(7) ų.D _calc.=1.875 mg m^–3, D_obs=1.600 mg m^–3,F(000)=576, =13.14 cm^–1. The final agreement factors for 1979 observed reflections [I>3(I)] were:R=0.062 andR _w=0.067. The vibrational spectra confirm the geometrical differences between the two thiooxamidate molecules.     

The crystal structure of 5-amino-2-nitrobenzoic acid

The crystal structure of 5-amino-2-nitrobenzoic acid (5A2NB) was determined by the X-ray diffraction method. The 5-amino-2-nitrobenzoic acid crystallizes in the monoclinic P2₁/c space group with a = 3.898(2) Å, b = 13.531(3) Å, c = 14.301(3) Å, and = 90.83(3)°. The adjacent molecules form a cyclic dimmer by intermolecular hydrogen bonds of type O—HsO with their carboxyl groups. In the crystal structure NH₂ group forms a three-center hydrogen bond with oxygen atoms of NO₂ group. The IR spectrum and thermal properties of acid are discussed.     

Refined crystal structure of kuzmenkoite

The structure of the mineral kuzmenkoite found in the Lovozero massif (the Kola Peninsula) was reinvestigated by the X-ray diffraction analysis. This mineral belongs to the labuntsovite family and differs from other members of this family by the absence of Na atoms, a high Mn content, and the new type of filling frame-work channels because of the replacement of Na atoms by H₂O molecules and H₃O groups. It was found that the disorder of atoms in the channels leads to lowering of the symmetry to Cm.     

Disordered crystal structure of chlorodifluoroacetamide

The crystal structure of chlorodifluoroacetamide has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/n witha = 7.401(6),b = 8.123(6),c = 8.431(6) Å, = 104.48(5) °, andD = 1.52 gcm^–3 forZ = 4. The finalR factor for 650 observed reflections is 0.059. The compound exists with a rotational disorder in the -CClF₂ group about the C-C bond. The occupancy factors for the major and minor conformations are 0.74 and 0.24, respectively.     

Principle of modular crystal structure

The principle of modular crystal structure has been formulated and the possibility of choosing a module of a specified structure type for its subsequent modular design is discussed. The modular characteristics of some structure types based on cubic close packing (fundamental and basic modules and the module that can be used to obtain a certain variety of modular structures related to the initial parent type) are described. Possible ways to obtain such a module and the algorithm for choosing it are considered. A comparative analysis of the theoretically derived module with the modules of experimentally determined modular structures is performed by the example of spinelloids (materials with spinel-like structure).     

The crystal structure of dimethyl 4-methoxy-2,3,5,6-tetrachlorophenyl phosphate

The crystal structure of dimethyl 4-methoxy-2,3,5,6-tetrachlorophenyl phosphate was determined by X-ray analysis. It crystallized in the space group P2 ₁/c (#14) with a = 9.446(2), b = 11.977(2), c = 12.306(2) Å, = 96.55(1)°, V = 1383.1(4) ų, D _calc = 1,665 5/cm³, and Z = 4.     

The molecular and crystal structure of the Steroidal Alkaloid Aculeamine

A new solanocapsine-type alkaloid named aculeamine has been isolated from roots of Solanum aculeatum and its structure has been established by X-ray analysis as 22,26-epimino-23β-methoxy-16α,23-epoxy-5α,25αH,25βH-chloestane-3β-ol. The compound crystallizes in the hexagonal space group P6₁ with the lattice parameters a = b = 16.706, c = 17.056 Å, α = β = 90°, γ = 120°. The final residual value was R = 0.079.     

The role of surface and interface structure in crystal growth

Crystal growth occurs at the interface of a crystal and its growth medium. Due to the abrupt termination at the surface, at the interface the properties of the crystal will typically deviate from the bulk and this can affect the growth behaviour. Also the properties of the growth medium at the interface will typically differ from the bulk. In growth from solution, for example, the liquid will show ordering induced by the crystal surface or have a different composition. Here techniques to study such growth interfaces will be discussed together with examples of the effect that the properties of the interface can have on the growth.     

The molecular and crystal structure of 2-oxo-1-pyrrolidine-acetamide

C₆H₁₀N₂O₂, P1 , a = 6,607(2) Å, b = 8,538(2) Å, c = 6,392(2) Å, α = 102,43(2)°, β = 91,11(2)°, y = 79,82(2)°, V = 349,1 ų, Z = 2, D_m = 1,36 g × cm⁻³, D_x = 1,35 g × × cm⁻³, MoKα radiation, λ = 1.71069 Å, μ(MoKα) = 1.11 cm⁻¹. The structure was solved by direct methods. The parameters were refined by full matrix least squares technique to a final R = 0.088 for 834 reflections with ∥F₀∥ > 4σ(F₀). The dihedral angle between the least-squares plane through the pyrrolidine ring and that through the acetamide group is 90.4°. The N H … O hydrogen bonds connect molecules to form bands parallel to the z axis.     

The crystal structure of a cyclodecabis[1,2,3]selenadiazole

4,5,6,10,11,12-hexahydrocyclodeca[1,2-d6,7-d]bis[1,2,3]selenadiazole, C₁₀H₁₂N₄Se₂, crystallizes in triclinic space group P witha=5.4625(3),b=7.2091(4),c=8.3122(6) , =65.313(5), =77.476(5), =77.442(5)°,V=287.35(4) ³,Z=1. The structure was refined toR=0.031 andR _w=0.030 for 2018 observed reflections. The molecule lies on an inversion center. The cyclodecadiene ring adopts an elongated chair conformation. The near-zero torsion angle of the elongated chair lies at the ring-fusion bonds, with a magnitude of 2.9(3)°. The five atoms of the selenadiazole ring exhibit maximum deviation 0.005(2) from planarity, with the adjacent carbon atoms lying respectively 0.020(2) and 0.059(2) to the same side of this plane. The torsion angles about the bonds comprising the sides of the elongated chair vary in magnitude from 61.0(2)° to 55.7(2)°. The cyclodecadiene C=C bond lengths are 1.368(2) . The selenium-carbon bond length is 1.850(2) . The Se–N distance is quite long, 1.888(2) .     

X-ray crystal structure of 2-styrylpyridine

We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that is shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion.     

X-ray crystal structure of dichloropicric acid

Dichloropicric acid is orthorhombic, space groupP2₁2₁2₁; at 24°a=5.672(3),b=8.044(3),c=22.491(7) Å,D _x=1.929(2) g-cm^?3,V=1026(1) ų,Z=4. The phenolic OH group is intramolecularly hydrogen bonded to one of theortho nitro groups with an O...O distance of 2.524(5) Å. As a consequence, this nitro group is twisted out of the plane of the benzene ring by only 20.1° in spite of crowding by the adjacent chlorine atom which is only 2.764(3) Å from the O atom in the nitro group. The two non-hydrogen bonded nitro groups have twist angles of 73.9 and 84.1°. There is no evidence of intermolecular hydrogen bonding with any adjacent dichloropicric acid molecule.