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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.43 [2005] >
IJPAP Vol.43(11) [November 2005] >
| Title: | Effect of thiourea on the crystal structure of ammonium dihydrogen phosphate |
| Authors: | Jayarama, A
Dharmaprakash, S M |
| Keywords: | Crystal structure
Ammonium dihydrogen phosphate
Non-linear optical
Thiourea
Dielectric
Antiferroelectric |
| Issue Date: | Nov-2005 |
| Publisher: | CSIR |
| IPC Code: | C30B |
| Abstract: | The
crystal structure of thiourea mixed ammonium dihydrogen phosphate (ADP) was
determined at 116(2) K. Temperature variation of thermal vibrations signifies
the existence of a disordered character of atoms. The structure was solved
using SHELXS-97 and refined with SHELXL-97. A direct-method solution was calculated which provided positions of non-hydrogen atoms from the E-map.
Full-matrix least squares/difference Fourier cycles were performed to locate
the hydrogen atoms. All non-hydrogen atoms were refined with anisotropic
displacement parameters. The unique hydrogen on the nitrogen and the
half-weight hydrogen on the oxygen atom were refined as isotropic contributors
in the final cycles of refinement. It follows that the mechanism of the phase
transition is dominated by the disorder-like motion of the NH4+
ion rather than the PO4
tetrahedron |
| Page(s): | 859-862 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.43(11) [November 2005]
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