TY - JOUR

T1 - Coupling between cation and anion disorder in β-K2Ca3(CO3)4

AU - Rashchenko, Sergey V.

AU - Ignatov, Mark A.

AU - Shatskiy, Anton F.

AU - Arefiev, Anton V.

AU - Litasov, Konstantin D.

PY - 2024/6/1

Y1 - 2024/6/1

N2 - Since the development of anionic group theory, the spatial arrangement of anionic groups in optical crystals has been believed to determine their functional, such as nonlinear optical, properties. At the same time, cation substitution, resulting in either the appearance of disordered cation sites in a crystal structure or the emergence of cation-ordered superstructures, has been widely used to control material properties. This work demonstrates the coupling between positional cation disorder and orientational disorder of (CO3)2- anions in the β modification of the recently described K2Ca3(CO3)4 material. In contrast to the α modification [P212121, a = 7.39134 (18), b = 8.8153 (2), c = 16.4803 (4) Å], where the ordered cation sublattice favors the non-centrosymmetric orientationally ordered arrangement of (CO3)2- anionic groups, positional cation disorder in β-K2Ca3(CO3)4 [Pnma, a = 7.5371 (2), b = 16.1777 (5), c = 8.7793 (3) Å] within the cation sublattice of the same topology leads to orientational disorder of (CO3)2- groups and the appearance of an inversion center in the average structure.

AB - Since the development of anionic group theory, the spatial arrangement of anionic groups in optical crystals has been believed to determine their functional, such as nonlinear optical, properties. At the same time, cation substitution, resulting in either the appearance of disordered cation sites in a crystal structure or the emergence of cation-ordered superstructures, has been widely used to control material properties. This work demonstrates the coupling between positional cation disorder and orientational disorder of (CO3)2- anions in the β modification of the recently described K2Ca3(CO3)4 material. In contrast to the α modification [P212121, a = 7.39134 (18), b = 8.8153 (2), c = 16.4803 (4) Å], where the ordered cation sublattice favors the non-centrosymmetric orientationally ordered arrangement of (CO3)2- anionic groups, positional cation disorder in β-K2Ca3(CO3)4 [Pnma, a = 7.5371 (2), b = 16.1777 (5), c = 8.7793 (3) Å] within the cation sublattice of the same topology leads to orientational disorder of (CO3)2- groups and the appearance of an inversion center in the average structure.

KW - carbonates

KW - high pressure

KW - isomorphism

KW - order-disorder

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85195509437&origin=inward&txGid=6c2541950e8ee6eb768fb86d9fb963d5

UR - https://www.mendeley.com/catalogue/050478aa-6feb-3838-90f0-d510279fb4b8/

U2 - 10.1107/S1600576724002292

DO - 10.1107/S1600576724002292

M3 - Article

VL - 57

SP - 665

EP - 669

JO - Journal of Applied Crystallography

JF - Journal of Applied Crystallography

SN - 0021-8898

IS - Pt 3

ER -