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Free keywords:
Microwave synthesis;
CoAPO-5;
Anisotropic optical absorption;
AFI molecular sieve;
Ultraviolet—visible single-crystal spectrum
Abstract:
Large CoAPO-5 crystals were synthesized by microwave heating of a fluoride-containing aluminophosphate gel. By polarization microscopy and polarization-dependent single-crystal ultraviolet—visible (UV—VIS) spectroscopy, the as-synthesized crystals show an optical anisotropy of light absorption. It is proposed that this effect originates from structure-related symmetry distortions of the tetrahedral Co2+ environment in the AFI framework. Consequently, the effect of anisotropic optical absorption can be taken as a proof for the incorporation of cobalt in the AFI framework.