Systematic, properties, and structure predictions of new borate materials

Abstract

New borates with the non-linear optical properties, obtained and investigated in Moscow State University in the last years, are reviewed. The positions of compounds in systematic were determined including complicate cases using topology and symmetry analysis of anionic radicals with the separation of blocks, typical for borate groups. Such approach revealed structural correlations between borates and silicates and led to prediction of new structures, two of which are realized. The origin of properties is connected with the highly polarizable electron density on lone pair or asymmetric bonds, presented in the structures. Experimental observation electron density distrubution has been made for Pb-hilgardite, a crystal with the high optical nonlinearity. Different approaches to the structure-properties relation are discussed. Dedicated to Prof. Ladislav Bohatý on the occasion of his 60th birthday

Recent progress in actinide borate chemistry

“…First, the building units of borates, BO 3 triangles and BO 4 tetrahedra tend to polymerize under a variety of conditions to form countless types of polyborate anions which provides numerous bonding modes to possibly coordinate the metal centers with a variety of geometric requirements. [58][59][60][61][62] Second, borate itself is a non-redox-active ligand under most conditions. This provides us an opportunity of controlling or at least predicting the oxidation states of actinides in products by controlling the oxidation states of actinides and the reduction potentials in the starting materials.…”

Chemical Cosubstitution-Oriented Design of Rare-Earth Borates as Potential Ultraviolet Nonlinear Optical Materials

“…With respect to borates, they reveal a wide optical transparency window, varied acentric structure types, high laser damage thresholds, and large polarizabilities. − As such, several commercial borate-based NLO materials have been developed, including β-BaB 2 O 4 (β-BBO), LiB 3 O 5 (LBO), KBe 2 BO 3 F 2 (KBBF), etc. Among borates, alkali and alkaline earth metals are the preferred alternative elements for designing borate-based NLO materials, mainly because those selected cations are free of d–d or f–f electronic transitions, which is beneficial for good transparency in the UV and even the deep-UV spectral region. , As a result, a variety of mixed alkali and/or alkaline earth metal borates, BaAlBO 3 F 2 , Na 2 CsBe 6 B 5 O 15 , Li 4 Sr­(BO 3 ) 2 , K 3 B 6 O 10 X (X = Br, Cl), , etc., have been frequently reported as front-line candidates for UV or deep-UV NLO materials.…”

Effects of the Orientation of [B5O11]7– Fundamental Building Blocks on Layered Structures Based on the Pentaborates

“…There are two types of arrangements between pentaborate blocks axes and the layer plane: parallel to the B-O layers or perpendicular to them. Combining the related pentaborate in this paper (Table S3 in the SI), it can be summarized that, when the pentaborate blocks axes are parallel to the B-O layer, it can be condensed into double layers (compounds 1 , 2 , 3 and A 2 A′ 2 ­B 10 O 17 ), whereas, when the pentaborate blocks axes are perpendicular to the B-O layer, it can be condensed into single layers (compound 4 and AM­B 5 O 9 ). − …”

“…With respect to the relationship between the pentaborate block axis and the layer plane, Figure d gives the expression more intuitively about parallel or perpendicular. Besides the title compounds, chains of block 5:[3Δ+2T] with a parallel orientation of the axis are known and exist in ezkurrite mineral . In contrast to that, no layer with the perpendicular block 5:[3Δ+2T] orientation is known in any natural crystals.…”

“…Besides the title compounds, chains of block 5:[3Δ+2T] with a parallel orientation of the axis are known and exist in ezkurrite mineral. 34 In contrast to that, no layer with the perpendicular block 5:[3Δ+2T] orientation is known in any natural crystals.…”