Three Mixed-Alkaline Borates: Na₂M₂B₂₀O₃₂ (M = Rb, Cs) with Two Interpenetrating Three-Dimensional B-O Networks and Li₄Cs₄B₄₀O₆₄ with Fundamental Building Block B₄₀O₇₇

Abstract

Three new mixed-alkaline borates NaMBO (M = Rb, Cs) and LiCsBO with unique structures were synthesized by the spontaneous nucleation method, and their structures were determined by single-crystal X-ray diffraction. The B-O networks of NaMBO (M = Rb, Cs) are constructed by two independent interpenetrating three-dimensional (3D) frameworks, which is the first case in anhydrous mixed-alkaline borate systems. In addition, LiCsBO shows high B-O polymerization with a new fundamental building block BO. Meanwhile, detailed structure comparisons containing the cation effect on the framework have been discussed. UV-vis-NIR diffuse reflectance spectra and the infrared spectra were measured. The band structures and the density of states were performed using density functional theory calculation.

The First Mixed Calcium Zinc Borate with a Flexible [B8O17] Fundamental Building Block and Short UV Cutoff Edge

“…Interestingly, the main outstanding characteristic of CaZnBO is that its BÀ O framework exhibits two independent interpenetrating 3D nets (Figure 1c). Topologically, the [B 8 O 17 ] FBBs can be described as the 6-connected nodes, the structure shows the interpenetrating double network with a Schläfli symbol of 4 12 .6 3 (Figure 1d). According to literature research, only a few borates as well as fluorooxoborates present the interpenetrating 3D framework, such as Na 2 M 2 B 20 O 32 (M = Rb, Cs), [12] β-Na 2 B 8 O 13 , [13] PbB 5 O 8 F, [14] Li 2 B 6 O 9 F 2 .…”

“…Topologically, the [B 8 O 17 ] FBBs can be described as the 6-connected nodes, the structure shows the interpenetrating double network with a Schläfli symbol of 4 12 .6 3 (Figure 1d). According to literature research, only a few borates as well as fluorooxoborates present the interpenetrating 3D framework, such as Na 2 M 2 B 20 O 32 (M = Rb, Cs), [12] β-Na 2 B 8 O 13 , [13] PbB 5 O 8 F, [14] Li 2 B 6 O 9 F 2 . [15] With respect to the cations in CaZnBO, the Ca atom is bonded to six O atoms to form the [CaO 6 ] polyhedron, then the two neighbouring [CaO 6 ] polyhedra are further connected by a couple of O( 4) atoms to give an isolated [Ca 2 O 10 ] dimmer (Figure S1).…”

K5B19O31: A Deep‐Ultraviolet Congruent Melting Compound

“…It is widely believed for the researchers that the dimension of the B−O framework is almost decreased with the A/B ratio (A=alkaline metals, B=boron) increased . The anhydrous alkali borates in ICSD were summarized in Table S2 in the Supporting Information.…”

“…Structure types of borates are considerably rich from the diversified connections between B and O elements. Normally, B atoms can coordinate with either three or four O atoms to form BO 3 triangles or BO 4 tetrahedra, which can further link by O atoms to make up various structure configuration, such as, isolated groups, infinite chains, infinite sheets and infinite networks . In order to express the B−O groups, the concept of fundamental building block (FBB) was put forward .…”

RbB11O16(OH)2: First Hydroxyl Rubidium Borate with the B‐O 2D Layer Featuring Large Birefringence in the Rb‐B‐O‐H System

“…Considering the advantage of alkali metals, as well as the introduction of cations with large atomic radii (Rb or Cs) may lead to special crystal structures, we focused on Rb‐B−O‐H system to explore new borates, and our efforts produced a new crystal, RbB 11 O 16 (OH) 2 , which shows interpenetrating 2D B−O layers. To our best knowledge, the reported hydroxy rubidium borates exhibit isolated B−O groups or 1D B−O chain.…”