Nature of the Color of Borates with "Anti-Zeolite" Structure

Tatyana B Bekker; Vladimir P Solntsev; Sergey V Rashchenko; Alexander P Yelisseyev; Alexey V Davydov; Alexander A Kragzhda; Alexander E Kokh; Artem B Kuznetsov; SoHyun Park

doi:10.1021/acs.inorgchem.7b03134

Nature of the Color of Borates with "Anti-Zeolite" Structure

Inorg Chem. 2018 Mar 5;57(5):2744-2751. doi: 10.1021/acs.inorgchem.7b03134. Epub 2018 Feb 19.

Authors

Affiliations

¹ Sobolev Institute of Geology and Mineralogy , Siberian Branch of Russian Academy of Science , 630090 Novosibirsk , Russia.
² Novosibirsk State University , 630090 Novosibirsk , Russia.
³ Novosibirsk State University of Architecture, Design and Arts (NSUADA) , 630099 Novosibirsk , Russia.
⁴ Crystallography Section, Department of Earth and Environmental Sciences , Ludwig-Maximilians University , 80333 Munich , Germany.

PMID: 29457896
DOI: 10.1021/acs.inorgchem.7b03134

Abstract

Crystals of the Mn _xBa₁₂(BO₃)_{8-2 x}F_{8 x} phase were grown from a high-temperature solution. This new fluoride borate is built of positively charged [Ba₁₂(BO₃)₆]⁶⁺ blocks, the so-called "anti-zeolite" pattern. Using X-ray single-crystal diffraction, the bulk atomic arrangement in the centrosymmetric tetragonal unit cell in I4/ mcm could be elucidated. Crystals of the (MnF₆)^4- group-containing solid solution Mn _xBa₁₂(BO₃)_{8-2 x}F_{8 x} are dark brown in color in contrast to the differently colored crystals of (LiF₄)^3- group-containing "anti-zeolite" LiBa₁₂(BO₃)₇F₄ ( P4₂ bc). According to the electron spin resonance and optical spectroscopic investigation, the absorption spectrum of LiBa₁₂(BO₃)₇F₄ crystals results from the absorption of light by both exciton and free charge carriers and can be tuned by varying the initial composition of the high-temperature solution.