Bridging the Salt-Inclusion and Open-Framework Structures: The Case of Acentric Ag<sub>4</sub>B<sub>4</sub>O<sub>7</sub>X<sub>2</sub> (X = Br, I) Borate Halides
Sergey N. Volkov, Dmitri O. Charkin, M. Yu. Arsent’ev, Alexey V. Povolotskiy, S. Yu. Stefanovich, В. Л. Уголков, Maria G. Krzhizhanovskaya, Vladimir V. Shilovskikh, Р. С. Бубнова
Abstract
An acentric borate family, Ag4B4O7X2 (X = Br, I), has been prepared by slow cooling stoichiometric melts in evacuated silica ampules. Their crystal structure is comprised of two porous interpenetrating frameworks and demonstrates a further development of the “salt-inclusion” architecture toward a “covalent-inclusion” structure. The (Ag2X)+ sublattice shows strong anharmonic vibrations. Thermal expansion is strongly anisotropic because of the presence of condensed rigid kernite boron–oxygen chains aligned perpendicular to the c axes.
Topics & Concepts
ChemistryAcentric factorBoronCrystallographyStoichiometryCrystal structureCovalent bondAnisotropyPhysical chemistryOrganic chemistryPhysicsQuantum mechanicsCrystal Structures and PropertiesMetal-Organic Frameworks: Synthesis and ApplicationsAdvanced Condensed Matter Physics