Synthesis, crystal structure, and properties of pentadecafluorotetraantimonate(III) CsRb2Sb4F15

• A new compound CsRb2Sb4F15 (I) was obtained.
• The crystal structure of the compound I is isle-like.
• The isostructural character of the compounds CsRb2Sb4F15 (I) and Cs3Sb4F15 (II) has been established.
• The specific polarizability in the complex compound (I) attains the value of 5.8 × 10−5 S/cm at 450 K.

A new compound CsRb2Sb4F15 (I) has been synthesized, and its crystal structure (monoclinic syngony: a = 7.9863(3), b = 28.594(1), c = 8.0319(3) Å, β = 116.60(1), space group P21/c) has been determined. The structure of I is composed of complex [Sb2F7]− and [SbF4]− anions and Cs+ and Rb+ cations, which link structural units into a framework through ionic bonds. The isostructural character of the compounds CsRb2Sb4F15 (I) and Cs3Sb4F15 (II) has been established. It has been demonstrated that fluorine ions diffusion is a predominant type of ionic motions in the fluoride sublattice of the compound I above 420 K. The comparison of ionic conductivities in K3Sb4F15, Cs3Sb4F15, and CsRb2Sb4F15 complexes has been performed. The factors determining the value of ionic conductivity in these compounds have been discussed.

A new compound CsRb2Sb4F15 has been synthesized, and its crystal structure has been determined. The structure is composed of complex [Sb2F7]− and [SbF4]− anions and Cs+ and Rb+ cations, which link structural units into a framework through hydrogen bonds. The isostructural character of the compounds CsRb2Sb4F15 and Cs3Sb4F15 has been established. The comparison of ionic conductivities in K3Sb4F15, Cs3Sb4F15, and CsRb2Sb4F15 complexes has been performed.Figure optionsDownload as PowerPoint slide