The title compound, C(16)H(15)NO(6), crystallizes with two symmetry-independent mol-ecules in the asymmetric unit. The crystal structure is stabilized by inter-molecular C-H⋯O and N-H⋯O hydrogen bonds, and intra-molecular C-H⋯O hydrogen bonds. In addition, the crystal structure exhibits two inter-molecular C-H⋯π inter-actions.

The asymmetric unit of the title co-crystal, C6H7N3O·0.5C4H6O4, comprises one N'-hy-droxy-pyridine-2-carboximidamide mol-ecule and half a succinic acid mol-ecule (the whole molecule is generated by inversion symmetry). In the crystal, mol-ecules are assembled into columns along [110], via strong N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds.

The solid solution, sodium [iron(III)/manganese(II)] tris-(orthophosphate), Na₃.₄Mn₀.₄Fe₁.₆(PO₄)₃, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe)₂(PO₄)₃] framework is built up from an (Mn/Fe)O₆octa-hedron (site symmetry 3.), with a mixed Mn/Fe occupancy, and a PO₄ tetra-hedron (site symmetry .2). The Na⁺ cations are distributed...

The possibility of a physical rotational symmetry for a quasicrystal is discussed and the minimal tensorial rank which is necessary to detect such a symmetry is shown to be simply related to the order of a symmetry rotation. For icosahedral symmetry, in particular, the minimal rank is 5 which means that "ordinary" linear (i.e. first order) behaviour (in the termal, electromagnetic, déformation ...

The space-group symmetry of a crystal structure imposes a point-group symmetry on its diffraction pattern, giving rise to so-called symmetry-equivalent reflections. Instances in macromolecular crystallography are discussed in which the symmetry in reciprocal space is broken, i.e. where symmetry-related reflections are no longer equivalent. Such a situation occurs when the sample suffers from si...

Binary compounds $A$Bi ($A$ = K, Rb, Cs) crystallize in P2$_1$/c structure containing both clockwise and anticlockwise chiral chains of Bi atoms. Electronic band exhibits the insulating nature these systems, with gap about $0.25$ eV. The presented study dynamical properties confirm a stability system symmetry. crystal contains quasi-one-dimensional chains, exhibiting four-fold-like rotational `...