C 1 NQR , Crystal Structure , and Pyroelectricity of 2 , 3 - Dichloro - l , 4 - naphthoquinone *
نویسندگان
چکیده
The C1 NQR spectra of the two phases (phases I and II) of 2,3-dichloro-l,4-naphthoquinone were studied from 77 to 394 K. The crystal structure determination of the triclinic phase (phase I) was refined by single crystal X-ray diffraction. Phase I crystallizes in the space group C/-P1. The unit cell (Z = 4) has the dimensions a = 1614.3(4) pm, 6 = 828.1 (3) pm, c = 733.2(3) pm, a = 67.02(l)°, /? = 82.55(1)°, y = 89.77(1)°. In the temperature range 4 3 9 ^ 7 ^ , , / K ^ 4 4 7 a unidirectional phase transition I —> II is observed. Phase II is orthorhombic, space group C2V-Pb21a. The bond distances d<c-cn and the C1 NQR frequencies correlate quite well according to the theory: v(Cl) ~ (rf(c-ci)) The multiplicity of the C1 NQR spectra is discussed. Pyroelectricity studies on phase II are reported. The pyroelectric coefficient depends little on the temperature, 8.3 ^ p/\iC m~ K ~ 1 ^ 10.7 in 103 ^ T/K ^ 343.
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für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...
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