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Exploration of New Birefringent Crystals in Bismuth d 0 Transition Metal Selenites
Author(s) -
Gong YaPing,
Hu ChunLi,
Kong Fang,
Mao JiangGao
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201806328
Subject(s) - bismuth , isostructural , crystallography , materials science , natural bond orbital , transition metal , oxide , octahedron , metal , hydrothermal circulation , crystal structure , inorganic chemistry , chemistry , molecule , metallurgy , catalysis , biochemistry , organic chemistry , seismology , geology
The first examples of bismuth fluoride selenites with d 0 ‐TM/Te VI polyhedrons, namely, Bi 4 TiO 2 F 4 (SeO 3 ) 4 ( 1 ), Bi 4 NbO 3 F 3 (SeO 3 ) 4 ( 2 ), Bi 4 TeO 4 F 2 (TeO 3 ) 2 (SeO 3 ) 2 ( 3 ), Bi 2 F 2 (MoO 4 )(SeO 3 ) ( 4 ) and Bi 2 ZrO 2 F 2 (SeO 3 ) 2 ( 5 ) have been successfully synthesized under hydrothermal reactions by aliovalent substitution. The five new compounds feature three different types of structures. Compounds 1 – 3 , containing Ti IV , Nb V and Te VI respectively, are isostructural, exhibiting a new 3D framework composed of a 3D bismuth oxyfluoride architecture, with intersecting tunnels occupied by d 0 ‐TM/Te VI octahedrons and selenite/tellurite groups. Interestingly, compound Bi 4 TeO 4 F 2 (TeO 3 ) 2 (SeO 3 ) 2 ( 3 ) is the first structure containing Se IV and mixed‐valent Te IV /Te VI cations simultaneously. Compound 4 features a new 3D structure formed by a 3D bismuth oxyfluoride network with MoO 4 tetrahedrons and selenites groups imbedded in the 1D tunnels. Compound 5 displays a novel pillar‐layered 3D open framework, consisting of 2D bismuth oxide layers bridged by the [ZrO 2 F 2 (SeO 3 ) 2 ] 6− polyanions. Theoretical calculations revealed that the five compounds displayed very strong birefringence. The birefringence values of compounds 1 – 3 , especially, are above 0.19 at 1064 nm, which are larger than the mineral calcite. Based on the structure and property analysis, it was found that the asymmetric SeO 3 groups (and TeO 3 in compound 3 ) displayed the largest anisotropy, compared with the bismuth cations and the d 0 ‐TM/Te polyhedra, which is beneficial to the birefringence.