Abstract
The crystal structures of (NH 4 ) 2 BeF 4 have been refined at -84°C (paraelectric phase) and -140°C (ferroelectric phase). The three-dimensional data were collected on a four-circle automatic diffractometer with monochromatized Mo K α radiation. The final discrepancy factors are 0.039 (-84°C) and 0.036 (-140°C). The change of the distribution of hydrogen atoms in N(2)H 4 ion in the ferroelectric phase is due to the reorientation of this ion. In the ferroelectric phase, BeF 4 and NH 4 ions slightly deviate from the paraelectric structure, which results in stronger N–H…F hydrogen bonds. Because of the hydrogen bonds, N(21)H 4 and N(22)H 4 ions, which are considered to owe the occurence of ferroelectricity, order in opposite direction along the polar b axis respectively. This suggests that (NH 4 ) 2 BeF 4 is a ferrielectric rather than a ferroelectric.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
