α-, β-Pb4B2O7 and α-, β-Pb4B6O13: Polymorphism drives changes in structure and performance

Abstract

Introducing Pb 2+ cations with lone pair electrons in borates is efficient to form multiple crystalline forms. Here, we report two new compounds, α-Pb 4 B 2 O 7 and β-Pb 4 B 6 O 13 , which exhibit different crystal forms from the previously reported lead borates, β-Pb 4 B 2 O 7 and α-Pb 4 B 6 O 13 , respectively. Two sets of polymorphs: α-, β-Pb 4 B 2 O 7 and α-, β-Pb 4 B 6 O 13 , exhibit completely different crystal structures and diverse optical properties. Thermal gravimetric and differential scanning calorimetry (TG-DSC) and variable-temperature powder X-ray diffraction (XRD) analyses were performed to study their thermodynamic stabilities. Structure-property relationships were discussed through first-principles calculation. Notably, the new phases, α-Pb 4 B 2 O 7 and β-Pb 4 B 6 O 13 , have larger birefringence than their corresponding polymorphs due to the rearrangement of the functional groups in their structures.

LiGaF2(IO3)2: A mixed-metal gallium iodate-fluoride with large birefringence and wide band gap

“…But their thermal stabilities are poorer than those of pure inorganic crystals. As for borates, B-O units may not be the superior birefringent genes, but strong covalent B-O bonds could induce short absorption edges and large laser-induced damage thresholds [LIDTs] [23][24][25][26][27][28][29][30]. For example, Ca(BO 2 ) 2 achieves the deep-UV absorption edge, the large birefringence, and the high LIDTs, showing that it is an excellent deep-UV birefringent material [28] were obtained in a high yield of ∼80% (based on I) (Fig.…”

Thermally Triggered Isomerization in a Naphthalene‐Based Acylhydrazone with Solid‐State Optical Nonlinearity Response

“…), have become another exciting new branch of NLO crystalline materials. [ 5–8 ] Developing a promising approach for solid‐state NLO transformation strongly depends on the relative arrangement and orientation of the constituent functional molecules from a centrosymmetric packing to an acentric one with apparent NLO response change. In this regard, inorganic and organic‐inorganic hybrid NLO crystalline materials have been reported to activate SHG active response change by thermal energy.…”

“…In this regard, inorganic and organic‐inorganic hybrid NLO crystalline materials have been reported to activate SHG active response change by thermal energy. [ 5–8 ] By comparison, organic NLO crystals with concomitant solid‐state second‐order NLO properties change by thermal stimuli are rarely reported possibly due to their low melting point, low thermal stability and low laser‐induced damage threshold.…”

Na2SrB16O26: a new borate with independent interpenetrating B–O networks and deep-ultraviolet cutoff edge

“…6–9 In general, the B atoms can be sp 2 or sp 3 hybridized with the O atoms to constitute [BO 3 ] and [BO 4 ] groups, which can form a variety of FBBs through common vertex or common edge connections. 10–17 For example, typical FBBs include [B 2 O 5 ] units in Li 2 Na 2 B 2 O 5 , 18 [B 3 O 6 ] units in β-BaB 2 O 4 (BBO), 19 [B 3 O 7 ] units in LiB 3 O 5 , 20 CsB 3 O 5 , 21 [B 4 O 8 ] units in Li 6 B 4 O 9 , 22 and [B 7 O 16 ] units in Na 3 B 7 O 12 23 etc . The variety of the linkage modes of these FBBs leads to the flexible structure of borates which exhibit zero-dimensional (0D) isolated clusters, 1D chains, 2D layers, and 3D frameworks.…”