The sample of the title compound, C12H15N3S, chosen for study consisted of triclinic crystals twinned by a 180° rotation about the a axis. The five-membered ring adopts a twisted conformation. The dihedral angle between the phenyl ring and the mean plane of the thio-urea unit is 78.22 (8)°. In the crystal, molecules are linked via pairs of N-H⋯S hydrogen bonds forming inversion dimers.

The structure of the title compound, pentoxifylline, C(13)H(18)N(4)O(3), has been previously characterized as a triclinic polymorph [Pavelčík et al. (1989 ▶). Acta Cryst. C45, 836-837]. We have discovered the monoclinic form. There are no strong hydrogen bonds in the crystal structure, rather, moderate C-H⋯O hydrogen bonds are present, which serve to stabilize the three-dimensional architecture.

Octakis(m-tolyloxymethyl)naphthalene, the first Type I spider host produced, crystallises from tetraglyme forming a novel channel structure with the host molecule attaining exact D(2) symmetry. The (flexible) channel structure is retained for guest CS(2), the host now only having exact C(2) symmetry. The octa-sulfone octakis(m-tolylsulfonylmethyl)naphthalene is also of Type I in its triclinic D...

The title compound, [Fe(C(5)H(5))(C(15)H(14)NO(2))], is a monoclinic polymorph of the previously reported triclinic form [Shi et al. (2006 ▶). Acta Cryst. C62, m407-m410]. The polymorphs feature the same strong intra-molecular N-H⋯O=C hydrogen bonds, but show different packing modes. The mol-ecules in the monoclinic form associate into double chains via O-H⋯O=C and (Cp)C-H⋯O-H inter-actions.

Tetartohedral crystal twinning is discussed as a particular case of (pseudo)merohedral twinning when the number of twinned domains is four. Tetartohedrally twinned crystals often possess pseudosymmetry, with the rotational part of the pseudosymmetry operators coinciding with the twinning operators. Tetartohedrally twinned structures from the literature are reviewed and the recent structure dete...

The structure of triclinic disodium hafnium disilicate, Na2HfSi2O7, has been determined by laboratory powder X-ray diffraction and refined by the Rietveld refinement. The structure is a framework made of alternate layers of HfO6 octa-hedra and SiO4 tetra-hedra linked by common O atoms. Sodium atoms are located in the voids of the framework, aligned into tunnels along the [010] direction. Na2HfS...

In viruses belonging to the Birnaviridae family, virus protein 4 (VP4) is the viral protease responsible for the proteolytic maturation of the polyprotein encoding the major capsid proteins (VP2 and VP3). Infectious pancreatic necrosis virus (IPNV), the prototype of the aquabirnavirus genus, is the causative agent of a contagious disease in fish which has a large economic impact on aquaculture....

Triaqua(thiodiacetato)nickel(II) has been synthesized and studied by X-ray crystallography, thermal, spectral and magnetic methods. The compound crystallizes in the triclinic system, space group P 1, in contrast to the related compound [Ni(tda) (H2O)3] Æ H2O (orthorhombic) reported long time ago. As in other four Ni–tda derivatives, the metal atom exhibits an octahedral coordination and tda lig...

The crystal structure and electronic properties of the rhenium disulfide a triclinic system within density functional theory pseudopotential are investigated. It is shown that calculated primitive cell parameters angles local approximation in good agreement with experimental data. established observed direct-gap character related to interband transitions at point X. electrons energy spectrum ch...

the synthesis and single-crystal x-ray structure determination of the title compound [(bipy) , pb(0 ,cme) (o clo )] (1) and [(bipy) pb(clo ) ] (2) is described. compound (i) crystallizes in the triclinic space group p1(2), a= 7.384(2), b= 12.824(3), c= 10.622(6) a, ?= 73.41(2), ?= 80.98(2), ?= 73.68(2)', z= 2, and r =0.033 for 3408 independent reflections .compound (2) crystallizes in the ...