Structural Study of (NH4)4H2(SeO4)3 in the Low-Temperature Phase |
| T. Fukami, N. Higa Department of Physics and Earth Sciences, Faculty of Science University of the Ryukyus, Okinawa 903-0213, Japan and R.H. Chen |
| Received: October 7, 1999, revised version December 21, 1999 |
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| The crystal structure of tetraammonium dihydrogen triselenate, (NH4)4H2(SeO4)3, in the low-temperature phase at 141 K is studied by X-ray diffraction. The space group symmetry (triclinic P1) and the structure parameters are determined. By the shift of the Se atom from the center of the SeO4 tetrahedron, it is suggested that the (NH4)4H2 (SeO4)3 crystal in the low-temperature phase is ferroelectric with the electric dipole moment along the c-axis. The rotation of the SeO4 tetrahedron suggested by electron paramagnetic resonance measurements is discussed. |
| DOI: 10.12693/APhysPolA.97.663 PACS numbers: 61.66.Fn, 64.60.Fr |