TY - JOUR

T1 - Structural changes in Rochelle salt on phase transitions revisited in a multi-temperature single-crystal X-ray diffraction study

AU - Sharaya, Svetlana S.

AU - Zakharov, Boris A.

AU - Boldyreva, Elena V.

N1 - This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for SRF SKIF Boreskov Institute of Catalysis (FWUR-2024-0042) and the strategic academic leadership program 2018-2019 Priority 2030 at the Novosibirsk State University. The authors thank Dr Valeri A. Drebushchak and Professor Dmitry Chernyshov for fruitful discussion.

PY - 2024/4/1

Y1 - 2024/4/1

N2 - Phase transitions in Rochelle salt [sodium potassium l(+)-tartrate tetrahydrate] are revisited in a single-crystal X-ray diffraction multi-temperature study on cooling from 308 to 100 K across the high-temperature paraelectric (PE) $ ferroelectric $ low-temperature PE phase transition points. The results of structure refinement using three different models (a harmonic with and without disorder, and an anharmonic) were compared. The temperature dependencies of anisotropic displacement parameters (ADPs) and Ueq, which can be calculated directly from ADPs, for the low-temperature PE phase indicate clearly the dynamic nature of disorder of the K1 atoms. The structures of the low-temperature and the high-temperature PE phases are compared for the first time at multiple temperatures for each phase based on diffraction data collected from the same single crystal. The data indicate that the high-temperature and the low-temperature paraelectric phases are probably not two different phases, as was assumed in earlier works, but are structurally the same phase at different temperatures.

AB - Phase transitions in Rochelle salt [sodium potassium l(+)-tartrate tetrahydrate] are revisited in a single-crystal X-ray diffraction multi-temperature study on cooling from 308 to 100 K across the high-temperature paraelectric (PE) $ ferroelectric $ low-temperature PE phase transition points. The results of structure refinement using three different models (a harmonic with and without disorder, and an anharmonic) were compared. The temperature dependencies of anisotropic displacement parameters (ADPs) and Ueq, which can be calculated directly from ADPs, for the low-temperature PE phase indicate clearly the dynamic nature of disorder of the K1 atoms. The structures of the low-temperature and the high-temperature PE phases are compared for the first time at multiple temperatures for each phase based on diffraction data collected from the same single crystal. The data indicate that the high-temperature and the low-temperature paraelectric phases are probably not two different phases, as was assumed in earlier works, but are structurally the same phase at different temperatures.

KW - Rochelle salt

KW - anisotropic displacement parameter analysis

KW - disorder models

KW - molecular ferroelectrics

KW - paraelectric phases

KW - variable-temperature X-ray diffraction

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85189930048&origin=inward&txGid=5c19fd7f435c32abf0b2656429dc4295

UR - https://www.mendeley.com/catalogue/50a4b62d-32f2-31c7-84f1-17d1ff224df0/

U2 - 10.1107/S205252062400115X

DO - 10.1107/S205252062400115X

M3 - Article

C2 - 38441051

VL - 80

SP - 94

EP - 104

JO - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

JF - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

SN - 2052-5192

IS - Pt 2

ER -