Polymorphs of Rb3ScF6: X-ray and Neutron Diffraction, Solid-State NMR, and Density Functional Theory Calculations Study.
Inorg Chem
; 60(8): 6016-6026, 2021 Apr 19.
Article
en En
| MEDLINE
| ID: mdl-33825461
The crystal structures of three polymorphs of Rb3ScF6 have been determined through a combination of synchrotron, laboratory X-ray, and neutron powder diffraction, electron diffraction, and multinuclear high-field solid-state NMR studies. The room temperature (RT; α) and medium-temperature (ß) structures are tetragonal, with space groups I41/a (Z = 80) and I4/m (Z = 10) and lattice parameters a = 20.2561(4) Å, c = 36.5160(0) Å and a = 14.4093(2) Å, c = 9.2015(1) Å at RT and 187 °C, respectively. The high-temperature (γ) structure is cubic space group Fm3Ì
m (Z = 4) with a = 9.1944(1) Å at 250 °C. The temperatures of the phase transitions were measured at 141 and 201 °C. The three α, ß, and γ Rb3ScF6 phases are isostructural with the α, ß, and δ forms of the potassium cryolite. Detailed structural characterizations were performed by density functional theory as well as NMR. In the case of the ß polymorph, the dynamic rotations of the ScF6 octahedra of both Sc crystallographic sites have been detailed.
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01-internacional
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MEDLINE
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En
Revista:
Inorg Chem
Año:
2021
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Article
País de afiliación:
Francia
Pais de publicación:
Estados Unidos