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A new mechanism of anionic substitution in fluoride borates
Author(s) -
Rashchenko Sergey V.,
Bekker Tatyana B.,
Bakakin Vladimir V.,
Seryotkin Yurii V.,
Kokh Alexander E.,
Gille Peter,
Popov Arthur I.,
Fedorov Pavel P.
Publication year - 2013
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889813015756
Subject(s) - boron , fluoride , crystallography , substitution (logic) , chemistry , crystal structure , phase diagram , phase (matter) , stereochemistry , inorganic chemistry , organic chemistry , computer science , programming language
A comprehensive study of the BaF 2 –Ba 3 (BO 3 ) 2 phase diagram has revealed a significant difference between the two intermediate phases Ba 5 (BO 3 ) 3 F and Ba 7 (BO 3 ) 4− y F 2+3 y . The latter exhibited (BO 3 ) 3− ↔ 3F − anionic substitution which, unusually, strongly influences the solidus temperature. A comparison of the Ba 5 (BO 3 ) 3 F and Ba 7 (BO 3 ) 4− y F 2+3 y crystal structures, along with consideration of other compounds demonstrating (BO 3 ) 3− ↔ 3F − isomorphism, allows for the disclosure of the mechanism of (BO 3 ) 3− ↔ 3F − heterovalent anionic substitution in fluoride borates via [(BO 3 )F] 4− tetrahedral groups being replaced by four fluoride anions. No exception to this mechanism has been discovered among all known phases with (BO 3 ) 3− ↔ 3F − substitution.