Download citation
Download citation

link to html
The title compound, lead trimanganese tris(orthophosphate), has been synthesized by hydro­thermal methods. In this structure, only two O atoms are in general positions and all others atoms are in the special positions of the Imma space group. Indeed, the atoms in the Wyckoff positions are namely: Pb1 and P1 on 4e (mm2); Mn1 on 4b (2/m); Mn2 and P2 on 8g (2); O1 on 8h (m); O2 on 8i (m). The crystal structure can be viewed as a three-dimensional network of corner- and edge-sharing PO4 tetra­hedra and MnO6 octa­hedra, building two types of chains running along the b axis. The first is an infinite linear chain, formed by alternating MnIIIO6 octa­hedra and PO4 tetra­hedra which share one vertex. The second chain is built up from two adjacent edge-sharing octa­hedra (MnII2O10 dimers) whose ends are linked to two PO4 tetra­hedra by a common edge. These chains are linked together by common vertices of polyhedra in such a way as to form porous layers parallel to (001). These sheets are bonded by the first linear chains, leading to the appearance of two types of tunnels, one propagating along the a axis and the other along b. The PbII ions are located within the inter­sections of the tunnels with eight neighbouring O atoms in form of a trigonal prism that is capped by two O atoms on one side. The three-dimensional framework of this structure is compared with similar phosphates such as Ag2Co3(HPO4)(PO4)2 and Ag2Ni3(HPO4)(PO4)2.

Download citation
Download citation

link to html
In the title compound, C14H16BrN3O5, the N atoms adjacent to the carbonyl group in the five-membered ring are substituted by (1,3-dioxolan-2-yl)methyl groups. The fused ring system is essentially planar, with the largest deviation from the mean plane being 0.014 (2) Å for the C atom bearing the Br atom. The first oxolane ring, attached on the side of the N atom belonging to the pyridine ring, has an envelope conformation with one of the O atoms as the flap, whereas the second oxolane ring displays a twisted boat conformation. The two oxolane rings display envelope and twisted boat conformations. In the crystal, mol­ecules are linked by C—H...O hydrogen bonds, building chains parallel to the a-axis direction.

Download citation
Download citation

link to html
The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from Atlas cedar (Cedrus atlantica) essential oil, after reaction with di­bromo­carbene. The asymmetric unit contains two independent mol­ecules with similar conformations. Each mol­ecule is built up from fused six-and seven-membered rings and two three-membered rings. In both mol­ecules, the six-membered ring has an envelope conformation with the flap provided by the C atom of the ep­oxy ring, whereas the seven-membered ring displays a chair conformation. The crystal packing is governed only by van der Waals inter­actions. The absolute configuration was established from anomalous dispersion effects.

Download citation
Download citation

link to html
The title compound, C13H9N3O3, crystallizes with two identical but differently oriented mol­ecules in the asymmetric unit, the dihedral angle between the fused-ring systems of the two molecules being 64.39 (7)°. The two prop-2-ynyl chains are located on opposite sides of the mol­ecule and are nearly perpendicular to the fused ring plane, as indicated by the C—N—C—C torsion angles in the range 106.0 (3)–113.4 (3)°. In the crystal, the two mol­ecules are linked through C—H...O hydrogen bonds into dimers, which are subsequently linked by further C—H...O inter­actions, building a three-dimensional network.
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds