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The title compound, [Ba(C12H6O4)(H2O)2] n , is represented by a layer-like structure built of BaO8 polyhedra. The asymmetric unit contains a Ba(2+) ion, half a coordinating water mol-ecule and half a μ4-bridging naphthalene-1,8-dicarboxyl-ate (1,8-nap) ligand, the whole structure being generated by twofold rotational symmetry. The carboxyl-ate groups of the 1,8-nap ligands act as bridges linking four Ba(2+) ions, while each Ba(2+) ion is eight-coordinated by O atoms from four 1,8-nap ligands and two coordinating water mol-ecules. In the crystal, there are O-H⋯O hydrogen bonds involving the water mol-ecules and carboxyl-ate O atoms in the BaO8 polyhedra. Each BaO8 polyhedron is connected via corner-sharing water O atoms or edge-sharing ligand O atoms, forming a sheet parallel to the bc plane. These sheets stack along the a-axis direction and are connected via van der Waals forces only. The naphthalene groups protrude above and below the layers of the BaO8 polyhedra and there are voids of ca 208 Å(3) bounded by these groups. No residual electron density was found in this region. The crystal studied was twinned by pseudo-merohedry, with a refined twin component ratio of 0.5261 (1):0.4739 (1).

In the title compound, C20H22N2O3S, the oxazoline ring is planar (r.m.s. deviation = 0.045 Å) and forms dihedral angles of 47.24 (8) and 10.11 (8)° with the S- and C-bound phenyl rings, respectively. The nitro group lies to the same side of the molecule as the oxazoline ring but is orientated so as not to interact with the ring. Linear supramolecular chains along [010] are formedviaC—H...O and C—H...S contacts. Chains are consolidated into a three-dimensional architecture by C—H...π and van der Waals interactions.

In the solid state the title Schiff base, 0.58C(28)H(20)N(2)O(2)·0.42C(28)H(20)N(2)O(2), exists both as the keto-imino and as the enol-amino tautomer, which is manifested in the disorder of the H atom in the intra-molecular hydrogen-bonded ring. The naphthalene ring systems show some distortion, which is consistent with the quinoid effect. The ratio of the enol form refined to 58 (5)%. The mol-ecule has crystallographically imposed symmetry: a twofold axis passes through the central benzene ring. Crystals are built up of layers parallel to (010). Stacking interactions between the layers involve only standard van der Waals attraction forces between apolar groups. The alignment of the aromatic rings in neighbouring layers shows a herringbone motif. A weak C-H⋯O inter-action is observed.

The title compound, {[La(4)(CH(3)CO(2))(10)(C(2)O(4))(H(2)O)(2)]·2H(2)O}(n), exhibits a two-dimensional layered structure with the oxalate and acetate ligands acting as bridges. The asymmetric unit contains two crystallographically independent lanthanum(III) ions, half of an oxalate ligand, five acetate ligands, one coordinated water mol-ecule and one uncoordinated water mol-ecule. The coordination numbers of the two La ions are 9 and 10. Adjacent layers of the structure, which extend parallel to (100), are linked by O-H⋯O hydrogen bonds and are also held together by van der Waals inter-actions between the CH(3) groups of the acetate anions.

In the title compound, NH(4) (+)·(C(2)H(5)O)(2)PS(2) (-), the ammonium cation is connected by four charge-assisted N-H⋯S hydrogen bonds to four tetra-hedral O,O'-diethyl dithio-phosphate anions, forming layers parallel to (100). The polar and non-polar constituents of the layers are stacked alternately along [100]. Inter-lacing of the external ethyl groups through van der Waals inter-actions combines these layers into a three-dimensional structure.

Next to the monoclinic polymorph [Cheng et al. (2005 ▶). Acta Cryst. E61, m892-m894], the triclinic title compound, [Fe(4)(C(2)H(5)S)(2)(S(2))(CO)(12)], is the second known form of this composition. The structure is composed of an [Fe(2)(C(2)H(5)S)(S)(CO)(6)] subcluster, which is linked to its counterpart by an inversion centre located at the mid-point of the central disulfide bond. The Fe(2)S(2) core of each subcluster exhibits a butterfly-like shape, with two S atoms bridging two Fe atoms. In the subcluster, each Fe atom is coordinated in a distorted octa-hedral coordination by three terminal carbonyl C atoms, two S atoms and one Fe atom. The crystal packing is accomplished through van der Waals inter-actions.

The title compound, C40H40O9, is a product of the double crotonic condensation of bis(2-acetylphenoxy)-3-oxapentane with bis(2-formylphenoxy)-3,6-dioxaoctane. The title macromolecule includes the 31-crown-7-ether skeletal unit and adopts a saddle-like conformation. The two ethylene fragments have E configurations. The volume of the internal cavity of the macrocycle is approximately 125 Å3. In the crystal, the molecules are arranged at van der Waals distances.

The title compound, C(20)H(27)BrO(4), a 4-bromo-benzoyl derivative of a stereoisomer of glycerol menthonide, synthesized as part of a study of 3-carbon stereochemical moieties, crystallizes with two crystallographically independent mol-ecules in the asymmetric unit, the two mol-ecules differing only in one of the C-O-C-C torsion angles around the ester O atom [-106.5 (7) and 146.1 (6)°]. The two mol-ecules are crystallographically related by a pseudotranslation along the (011) diagonal of the unit cell, emulating a primitive monoclinic cell of half the volume. The translational symmetry is broken by the 4-bromo-benzoate groups. The crystallographic assignment of the absolute stereochemistry is consistent with having started with (-)-menthone, the acetal C atom is R and the secondary alcohol is R. This brings the bromo-benzoate into approximately the same plane as the menthyl ring and cis to the isopropyl group. The glycerol menthonide sections of the molecules interact with each other via C-H⋯O interactions, leading to the formation of chains either A or B molecules that stretch parallel to [010], forming column-shaped double chains. Interactions between neighboring columns are limited to van der Waals contacts.

The title compound, [Li2(C25H23BN4OP)2], features a centrosymmetric dimeric complex. The four-memberered Li2O2ring is exactly planar due to symmetry. The Li atom is four-coordinated by two O atoms and by two N atoms of two different pyrazole rings. The dihedral angle between two pyrazole rings bonded to the same B atom is 45.66 (9)°. The B—N—N—Li—N—N metalla ring adopts a boat conformation. The crystal packing is stabilized by van der Waals interactions only.

The molecular title compound, C20H22O6, was obtained by the reaction of ethyl 2-hydroxybenzoate with 1,2-dichloroethane. The molecule lies on a twofold rotation axis which passes through the middle of the central ethylene bridge. This group exhibits agaucheconformation with the corresponding O—C—C—O torsion angle being 73.2 (2)°. The C atoms of the carboxyl group, the aryl and the O—CH2group are coplanar, with an r.m.s. deviation of 0.01 Å. The two aryl rings form a dihedral angle of 67.94 (4)°. The ester ethyl group is disordered over two sets of sites with an occupancy ratio of 0.59 (2):0.41 (2). The crystal packing is dominated by van der Waals forces.

In the title compound, C18H18O6, the biphenyl moiety is twisted with a dihedral angle of 29.11 (10)°. The carbomethoxy groups form C—C—C—O torsion angles of −18.3 (3) and −27.7 (3)° with the attached rings, as a result of steric hindrances from the nearby methoxy groups. In the absence of stacking interactions and with no H...O contacts shorter than 2.7 Å, the packing is dominated by weaker van der Waals interactions.

In the title compound, 2C(17)H(18)N(2)O(6)·C(4)H(4)N(2) [systematic name: 3,5-dimethyl 2,6-dimethyl-4-(2-nitro-phen-yl)-1,4-di-hydro-pyridine-3,5-dicarboxyl-ate-pyrazine (2/1)], the complete pyrazine molecule is generated by crystallographic inversion symmetry. The center of the pyrazine ring lies on an inversion center. The nifedipine mol-ecules are linked into chains along the c axis through N-H⋯O hydrogen bonds, while the pyrazine mol-ecules are organized in the structure through van der Waals inter-actions.

The asymmetric unit of the title complex, (C(10)H(10)N(4))(C(10)H(9)N(4))[W(CN)(8)]·2H(2)O, contains two 4,4'-diazenediyldipyridinium, [H(2)(4,4'-azpy)](2+), two 4-(4-pyridyldiazen-yl)pyridinium, [H(4,4'-azpy)](+), cations, two [W(V)(CN)(8)](3-) anions, and four uncoordinated water mol-ecules. Each of the W centers is coordinated by eight CN groups in a slightly distorted square-anti-prismatic geometry. In the crystal structure, intra- and inter-molecular N-H⋯O, N-H⋯N and O-H⋯N hydrogen bonds link the cations and anions in an alternating fashion, forming a two-dimensional layered structure, in which they are further linked through the very weak π-π stacking inter-actions [shortest distance = 4.640 (2) Å] and van der Waals forces between adjacent layers, forming a three-dimensional supra-molecular network.

The title heterocyclic compound, C14H15N3O3, is a new synthetic molecule containing oxazolidine and quinoxaline rings. It is built up from two fused six-membered rings linked to a five-membered oxazolidin-2-one ring by a C2 chain. Both ring systems are essentially planar [maximum deviation = 0.894 (3) Å, r.m.s. deviation = 0.0043 Å]. The structure is held together by van der Waals forces [electrostatic interactions between dipoles, O...C = 3.002 (2) Å] between molecules and by weak π–π stacking between symmetry-related molecules, with an interplanar distance of 3.579 Å and a centroid–centroid distance of 3.800 (1) Å. Intermolecular C—H...O hydrogen bonds are also observed in the crystal structure.

In comparison with a previous crystallographic study [Goh et al. (2002). J. Solid State Chem. 168, 119–125] of the title compound, silver diniobium tris(disulfide) tetrathiophosphate(V), that reports a full occupation of the silver position and isotropic displacement parameters for the atoms, the current redetermination reveals a silver deficiency with a site-occupation factor of 0.88 (1) and reports all atoms with anisotropic displacement parameters. The structure of Ag0.88Nb2PS10 is composed of ∞1[Nb2PS10] chains, which are built up from pairs of distorted bicapped trigonal-prismatic [NbS8] polyhedra forming [Nb2S12] dimers and of tetrahedral [PS4] groups. These chains are connected via the statistically disordered Ag+ ions, forming double layers. Adjacent layers are stacked solely through van der Waals forces into a three-dimensional structure. Short and long Nb—Nb distances [2.880 (1) and 3.770 (2) Å, respectively] alternate along the chain and S22− and S2− anionic species are observed.

In the title compound, C29H34N2S2, the pyrazole ring is planar and both cyclohexane rings adopt chair conformations. The dihedral angles between the pyrazole ring and the two benzene rings are 59.9 (2) and 19.8 (2)°. The conformation and packing of the molecules in the unit cell are stabilized by a weak intramolecular C—H...S and C—H...N interactions, in addition to van der Waals forces.

In the title compound, C16H14ClNO3S, the dihedral angle between the almost-planar benzothiazole ring system [maximum deviation = 0.012 (3) Å] and the aromatic ring of the trimethoxyphenyl group is 15.56 (6)°. In the crystal, the molecules are arranged into layers parallel to the bc plane, held together only by weak van der Waals forces.

In the title compound, C12H9BrFNO, the dihedral angle between the aromatic rings is 51.39 (5)°; the C atom of the methoxy group is close to being coplanar with its attached ring (r.m.s. deviation = 0.0172 Å] and is oriented away from the pyridine ring. In the crystal, molecules interact by van der Waals forces.

The complete molecule of the title compound, C10H4N2S2, is generated by an inversion center situated at the mid-point of the bridging C—C bond. The bithiophene ring system is planar [maximum deviation = 0.003 (2) Å] and the central C—C bond length is 1.450 (2) Å. There are no significant intermolecular interactions in the crystal structure, which is stabilized by van der Waals interactions.

In the title compound, C19H18O, the cyclohexene ring has an envelope conformation with the methine C atom on the flap. The phenyl and methylphenyl rings form a dihedral angle of 85.93 (11)°. The crystal packing is consolidated by van der Waals forces and weak C—H...π interactions.

The title benzyl Grignard reagent, [Mg(2)Br(2)(C(7)H(7))(2)(C(4)H(10)O)(2)], was obtained by reaction of benzyl bromide with magnesium in diethyl ether, followed by crystallization from toluene. The asymmetric unit comprises one half-mol-ecule, the structural dimeric unit being generated by inversion symmetry with an Mg⋯Mg distance of 3.469 (2) Å. The Mg(II) atom exhibits a distorted tetrahedral coordination geometry. The crystal packing is defined by van der Waals inter-actions only.

In the title compound, C20H11Cl2F4N3, the central pyrazolo[1,5-a]pyrimidine unit is almost planar [the mean deviation from the best least-square plane through the nine atoms is 0.006 (2) Å]. The fluorobenzene ring is rotated out of this plane by 10.3 (3)°, whereas the dichlorobenzene ring is rotated by 46.2 (3)°. The crystal packing is dominated by Cl...Cl interactions of 3.475 (3) Å and van der Waals interactions.

The title compound, C(14)H(13)NO(4), was prepared through a palladium-catalysed Suzuki-Miyaura coupling reaction. The asymmetric unit comprises two mol-ecules related by pseudo-inversion symmetry. The dihedral angles between the benzene rings in the two mol-ecules are 44.30 (6) and 48.50 (6)° while those between the benzene ring and the nitro group are 6.54 (13) and 5.73 (10)°. The crystal packing is defined only by Van der Waals inter-actions.

The title compound, C15H13NO2, was prepared through a palladium-catalysed Suzuki–Miyaura coupling reaction. The dihedral angle between the biphenyl rings is 40.96 (6)°. The methoxy groups are twisted slightly out of the plane of the benzene ring [C—C—C—C torsion angles = −3.61 (18) and 12.6 (2)°]. The packing of the molecules is stabilized by van der Waals interactions.

In the title compound, C17H21N, the dihedral angle between the benzene ring and the imine group (—N=) is 5.1 (4)°. In the adamantane group, the C—C—C bond angles range from 107.88 (19) to 111.33 (17)°. Only weak van der Waals interactions contribute to the contribute to the packing of the molecules in the crystal..

In the title compound, C21H18Si, the coordination geometry around the Si atom is a slightly distorted tetrahedron with C—Si—C angles in the range 106.05 (11) to 110.58 (10) ° and Si–C bond lengths in the range 1.855 (2) to 1.883 (3) Å. The alkyne C—C bond length is 1.167 (4) Å. The dihedral angles between the three phenyl rings are 63.89 (7), 86.38 (7) and 70.51 (8)°. In the crystal, molecules interact only by van der Waals forces.

The asymmetric unit of the title compound, C40H60O5S, comprises two diastereomers related, except for the chiral camphor groups, by a pseudo-inversion centre. In both diasteromers, the camphor sulfate moiety maintained the absolute configuartion (R,S) of the precursor. However, the absolute configurations at the methine C atoms are of opposite chirality. Both molecules reveal intramolecular O—H...O hydrogen bonds, whereas van der Waals interactions define the crystal packing.

In the title compound, C4H8N3O+·C4H3O4−, the cations and anions are linked through N—H...O hydrogen bonds making a ionic pair with an R22(8) ring motif. These ionic pairs are further connected through another N—H...O hydrogen bond, leading to an R66(16) ring motif around the inversion centres of the unit cell. These approximately planar aggregates are further connected through weak van der Waals interactions in the unit cell. The anions have a characteristic intramolecular O—H...O hydrogen bond with a self-associated ring S(7) motif.

The title compound, C12H18N4O2SSi, was synthesized to be employed in a Julia–Kocieński olefination. In the molecule, the dihedral angle between the phenyl ring and the tetrazole ring is 41.50 (5)°. The significantly longer Si—C(methylene) bond [1.8786 (13) Å] and the shortened adjacent C—C bond [1.5172 (18) Å], as well as the significant deviation of the corresponding Si—C—C angle [114.16 (9)°] from the ideal tetrahedral angle, can be attributed to the β-effect of silicon. In the crystal, molecules are held together by van der Waals interactions.

The Sn atom in the title compound, [Sn(CH(3))(2)(C(13)H(10)NO(2))(2)], has a highly distorted octa-hedral coordination with the equatorial plane made up of four O atoms from two N-benzoyl-N-phenyl-hydroxy-laminate ligands and the axial positions occupied by two methyl groups. The crystal structure is stabilized by van der Waals inter-actions.

The title compound, C(11)H(17)Br, has crystallographically imposed mirror symmetry in the solid state with mol-ecules bis-ected by mirror planes parallel to the crystallographic ac plane (five C atoms, three H atoms and the Br atom lie on the mirror plane). The asymmetric unit contains one half-mol-ecule. The crystal packing is stabilized only via weak non-specific van der Waals inter-actions.

The title complex, [CuBr(C(6)H(4)NO(3))(H(2)O)](n), exhibits a layered structure which is stabilized by inter-molecular O-H⋯O and O-H⋯Br(-) hydrogen bonds, van der Waals forces and π-π inter-actions [centroid-centroid distance = 3.747(4) Å] between the parallel pyridine rings from two neighboring layers.

In the pyramidal-shaped molecule of the title compound, C10H12Br4, the four terminal Br—C bond distances are nearly identical, ranging from 1.964 (4) to 1.974 (4) Å. The Br...Br distance of 3.6553 (7) Å indicates van der Waals contacts between molecules in the crystal structure.

In the title compound, [CdI2{(C6H5)3PO}2], the CdII atom is ligated by two I atoms and two O atoms from two triphenylphosphine oxide ligands in a disorted tetrahedral arrangement. While the O—Cd—I angles vary from 106.67 (7) to 111.23 (7)°, the O—Cd—O angle is 88.60 (10)° and the I—Cd—I angle angle is 125.47 (2)°. The crystal structure is stabilized by van der Waals forces only.

In the title compound, C8H8S6, the five-membered rings form a dihedral angle of 25.06 (9)°. In the absence of short intermolecular contacts, the molecules are packed by van der Waals forces in the crystal.

In the title compound, C12H11N3O3, the dihedral angle between the 3-nitrobenzaldehyde and 5-amino-3,4-dimethyl-1,2-oxazole moieties is 2.46 (12)°. The molecule is close to planar, the r.m.s. deviation for the non-H atoms being 0.028 Å. The packing only features van der Waals interactions between the molecules.

The quaternary title compound, caesium chromium(III) hepta-thio-diphosphate(V), CsCrP(2)S(7), has been synthesized using the reactive halide flux method. It is isotypic with other AMP(2)S(7) (A = alkali metal; M = Cr, V or In) structures and consists of two-dimensional (∞) (2)[CrP(2)S(7)](-) layers extending parallel to (001) which are separated from each other by Cs(+) ions (symmetry 2). The layer is built up from slightly distorted octa-hedral [CrS(6)] units (symmetry 2) and bent [P(2)S(7)] units consisting of two corner-sharing [PS(4)] tetra-hedra. The [CrS(6)] octa-hedra share two edges and two corners with the [PS(4)] tetra-hedra. There are only van der Waals inter-actions present between the layers. The Cs(+) ions are located in this van der Waals gap and stabilize the structure through weak ionic inter-actions. The classical charge balance of the title compound can be expressed as [Cs(+)][Cr(3+)][P(5+)](2)[S(2-)](7.).

The title compound, C22H20N2O, was obtained from the condensation reaction of 3-formylbenzonitrile, 2-naphthol and pyrrolidine. There are two molecules in the asymmetric unit, having similar conformations. Intramolecular O—H...N and C—H...O hydrogen bonds occur, with only van der Waals forces between molecules. The dihedral angles between the naphthalene ring system and the phenyl ring in the two molecules are 75.28 (10) and 76.07 (11)°. The five-membered rings adopt half-chair conformations.

In the crystal structure of the title compound, C18H12N2OS, centrosymmetric dimers are stabilized both by van der Waals interactions and by two types of intermolecular O—H...N hydrogen bonds. In addition, an intramolecular C—H...S hydrogen bond is observed. The dihedral angles between the central ring and the two pendant phenyl rings are 7.4 (1) and 45.06 (9)°.

In the title compound, C(18)H(16)Br(2)O(2), the dihedral angle between the aromatic rings is 35.55 (17)° and the cyclohexyl ring adopts a chair-like conformation. In the crystal, molecules are linked by van der Waals forces.

The molecule of the title compound, C22H26Si2, is centrosymmetric. The dihedral angle between the central benzene ring and its phenyl substituents is 67.7 (2)°. The crystal packing is stabilized by van der Waals forces.

In the title compound, C22H27NO4, the mean planes of the two benzene rings form a dihedral angle of 73.54 (13)°. One of the methyl groups is disordered over two sites, with site occupation factors of 0.47 (15) and 0.53 (15). The crystal packing is controlled by van der Waals forces and a possible C—H...O interaction, forming a chain running parallel to the a axis.

In the title structure, [Pb(C(5)H(3)N(2)O(2))(2)](n), the Pb(II) ion is six-coordinated by two pyridazine-3-carboxyl-ate ligands via N and O atoms, with the carboxyl-ato O atoms acting as bidentate and bridging adjacent Pb(II) ions, giving rise to catenated mol-ecular ribbons propagating along the a-axis direction. The ribbons are connected by C-H⋯O hydrogen bonds and van der Waals inter-actions.

In the title compound, C8H9ClN2O2, the two planar fragments, i.e. the chlorophenyl and C—C(=O)—N groups, are inclined at 14.93 (17)°. In the crystal, relatively weak intermolecular N—H...N, C—H...O and N—H...O hydrogen bonds connect the molecules into layers. The hydrophobic parts of molecules stick outside these layers and are connected with the neighbouring layers only by van der Waals contacts and Cl...Cl interactions [3.406 (2) Å].

In the title compound, C11H10BrNO2, the dihedral angle between the five- and six-membered rings of the phthalamide system is 1.00 (16)°. There are no significant intermolecular interations except for van der Waals contacts.

The complete molecule of the title compound, C22H16N2O4, is generated by a crystallographic centre of inversion. The plane of the central aromatic ring is tilted by 11.85 (4)° with respect to the outer aromatic ring. The crystal packing is determined by van der Waals interactions, with stair-like stacking between adjacent aromatic rings. The stacks are staggered and each layer is approximately 3.8 Å from the next. The closest intermolecular contact (approximately 2.42 Å) is between an O atom and a vinyl H atom.

In the title compound, C10H7ClN4, the quinoline ring system is planar [maximum deviation 0.0035 (10) Å]. The crystal structure is stabilized by van der Waals and π–π stacking interactions [centroid–centroid distance 3.6456 (17) Å].

The title mol-ecule, C(14)H(18)Cl(4), possesses a crystallographically imposed inversion centre, which coincides with the centre of benzene ring. In the absence of classical inter-molecular inter-actions, van der Waals forces help the mol-ecules to pack in the crystal.

In the title compound, C24H25NO8S, the indole unit is planar and makes a dihedral angle of 79.73 (11)° with the phenyl ring of the sulfonyl substituent. The molecules in the unit cell are stabilized by C—H...O and C—H...π intermolecular interactions in addition to van der Waals forces.

The new layered ternary sulfide, Nb(1.30)Cr(0.70)S(5), niobium chromium penta-sulfide, is isostructural with the solid solution Nb(1+x)V(1-x)S(5) and belongs to the FeNb(3)Se(10) structure type. Each layer is composed of two unique chains of face-sharing [NbS(8)] bicapped trigonal prisms (m symmetry) and edge-sharing [MS(6)] (M= Nb, Cr) octa-hedra (m symmetry). One of the two metal sites is occupied by statistically disordered Nb and Cr atoms, with 0.3 and 0.7 occupancy, respectively. The chains are connected along the c axis, forming two-dimensional layers, which then stack on top of each other to complete the three dimensional structure. As a result, an undulating van der Waals gap is found between the layers.