@article{OrgzallFrancoRecketal.2005,
  author    = {Orgzall, Ingo and Franco, Olga and Reck, Guenter and Schulz, Burkhard},
  title     = {High-pressure studies on fluorine substituted 2,5-di(phenyl)-1,3,4-oxadiazoles},
  issn      = {0022-2860},
  year      = {2005},
  abstract  = {Results are presented from structural and high-pressure investigations on four differently but symmetrically fluorine substituted 2,5di(phenyl)-1,3,4-oxadiazoles. The substitution pattern includes the para-, meta-, or ortho- substitution and the fully fluorinated 2,5-bis(pentafluorophenyl)-1,3,4-oxadiazole. The crystal structure depends on the molecular structure and results in a different high-pressure behavior. Parameters for the Murnaghan equation of state (EOS) are determined for every compound and the anisotropic pressure response of the crystal lattice is discussed. Although the EOS parameters, bulk modulus K. and its pressure derivative K'(o) are of the same order of magnitude for all four compounds, the anisotropy of strain is noticeably different. (c) 2005 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{FrancoOrgzallRecketal.2005,
  author    = {Franco, Olga and Orgzall, Ingo and Reck, G{\"u}nter and Stockhause, Sabine and Schulz, Burkhard},
  title     = {Structure and high-pressure behavior of 2,5-di-(4-aminophenyl)-1,3,4-oxadiazole},
  issn      = {0022-3697},
  year      = {2005},
  abstract  = {The crystalline structures of two modifications of a compound containing the oxadiazole ring, 2,5-di-(4- aminophenyl)-1,3,4-oxadiazole (DAPO) were determined. One of these modifications contains water molecules in the crystal structure, which is observed for the first time for an oxadiazole crystal. Both crystals show an orthorhombic structure. The water free modification, DAPO L belongs to the space group Pbca (61) and has the lattice parameters: a = 13.461(5), b = 7.937(3) and c = 22.816(8) angstrom (CCDC 246608). The water containing pseudo-polymorph, DAPO 11, has the space group Cmcm (63) and the lattice parameters: a = 16.330(5), b = 12.307(2) and c = 6.9978(14) angstrom (CCDC 246609). To gain information on the inter molecular interactions within the crystals, X-ray experiments under compression at ambient temperature and under heating at vacuum conditions were performed. Neither DAPO I nor DAPO II undergo phase transitions in the ressure range up to 5 GPa, as could be concluded from X-ray and Raman experiments. X-ray and calorimetric studies indicate that DAPO II dehydrates into DAPO I under increasing temperature. Structural considerations suggest a two-stage process. The compression behavior of both substances is well described by the Murnaghan equation of state (MEOS) and the values of the bulk modulus and its pressure derivative are determined for these crystals. Additionally, in the case of DAPO I, also the thermal expansion coefficient an was measured. (c) 2005 Elsevier Ltd. All rights reserved},
  language  = {en}
}