Expanding the chemistry of borates with functional [BO2]− anions

Abstract

More than 3900 crystalline borates, including borate minerals and synthetic inorganic borates, in addition to a wealth of industrially-important boron-containing glasses, have been discovered and characterized. Of these compounds, 99.9 % contain only the traditional triangular BO3 and tetrahedral BO4 units, which polymerize into superstructural motifs. Herein, a mixed metal K5Ba2(B10O17)2(BO2) with linear BO2 structural units was obtained, pushing the boundaries of structural diversity and providing a direct strategy toward the maximum thresholds of birefringence for optical materials design. 11B solid-state nuclear magnetic resonance (NMR) is a ubiquitous tool in the study of glasses and optical materials; here, density functional theory-based NMR crystallography guided the direct characterization of BO2 structural units. The full anisotropic shift and quadrupolar tensors of linear BO2 were extracted from K5Ba2(B10O17)2(BO2) containing BO2, BO3, and BO4 and serve as guides to the identification of this powerful moiety in future and, potentially, previously-characterized borate minerals, ceramics, and glasses.

Borates: A Rich Source for Optical Materials

“…It was also apparent that most borates discussed in this review are composed of traditional [BO 3 ] and [BO 4 ] units, and few borates contain fluorinated [BO 4−x F x ] tetrahedra. Recently, the discovery of linear [BO 2 ] units in K 5 Ba 2 (B 10 O 17 ) 2 (BO 2 ) provide more useful information to push the current limits of borates to a new height 587. We can imagine that the introduction of linear [BO 2 ] units in the structures of currently available B−O/F anionic framework will cause more interesting FBBs and configuration.…”

KEu2In3B12S13: a novel type of thioborate featuring B12S12 cluster and unique In6S6 12-membered ring

“…4,[11][12][13][14][15][16] In around recent ten years, there are only five studies addressing chalcogenoborates containing B 12 It is well known that borates are wonderful functional materials as either electrode materials for rechargeable batteries or second-order nonlinear optical (NLO) materials in the ultraviolet (UV) region. [20][21][22][23][24][25] On the other hand, chalcogenides are the most competitive candidates for NLO materials in the middle-infrared (MIR) region. [26][27][28][29][30][31][32][33] The combination of borates and chalcogenides has also demonstrated promising NLO and special magnetic properties.…”

Identical in Formula but Not Isotypic in Configuration: Discovery of a New Highly Polymerized [B12O24] Cluster in Cs3AlB6O12

“…In addition, borates containing isolated B–O/F groups usually have metal cations with strong covalence (like M = Zn, Be, Al, etc. ), in which the cations with a higher valence state can form rigid chemical bonds (M–O/F) and break the anionic framework into a 0D configuration because of their stronger coordination ability. , Among them, the low polymerization degree of isolated B m –O/F ( m < 6) groups, like [BO 2 ], [BO 3 ], [BO 4 ], [B 2 O 5 ], [B 3 O 6 ], and [B 5 O 10 ] units, is much more than that of the highly polymerized ones (∼97 vs 3%). ,− To date, the [B 18 O 36 ] cluster is the largest one in the anhydrous borates and is found in Sr 8 MB 18 O 36 (M = Mg, Zn, Cd) , and NaSr 7 AlB 18 O 36 series . Other highly polymerized 0D clusters B m -O/F ( m ≥ 6), like [B 6 O n ] ( n = 12, 14), [B 7 O 14 ], [B 9 O 21 ], [B 11 O 22 ], [B 12 O 24 ] units, etc., are also very limited and have only been discovered in few borates. − Studies have shown that the highly polymerized B–O clusters tend to form the same and certain configurations, like [B 12 O 24 ] and [B 18 O 36 ] units, in related compounds and are all in a cyclic formation constructed by [B 3 O 7 ] and [B 3 O 8 ] branches with an end-to-end model, and both types show identical formulas and structures. − ,, Of course, the discovery of such borates greatly enriched the structural chemistry of the borate system.…”