Crystal Structure of Deuterated Dicalcium Strontium Propionate, Ca2Sr(C2D5CO2)6in the Paraelectric and Ferroelectric Phases

Abstract

The absolute crystal structure of the deuterated dicalcium strontium propionate (DDSP) has been determined by the X-ray diffraction with a four-circle automatic diffractometer at three temperatures in each of the paraelectric and ferroelectric phases. The space group is determined to be D 4 4 -P4 1 2 1 2 or D 4 8 -P4 3 2 1 2 in the paraelectric phase with the R -factors less than 3% and to be C 4 2 -P4 1 or C 4 4 -P4 3 in the ferroelectric phase with the R -factors less than 5%. The molecular structure of the deuterated propionates is also elucidated and compared with that of the nondeuterated one. The comparison confirms the structure quite similar to each other, indicating no isotope effect on the molecular structure. The disordered arrangement of the propionate molecules on (001) plane is observed in the ferroelectric phase similarly to the nondeuterated DSP.