Versatile Coordination Mode of LiNaB8O13 and α- and β-LiKB8O13 via the Flexible Assembly of Four-Connected B5O10 and B3O7 Groups

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

A new borate, Na₂SrB₁₆O₂₆, was synthesized by the high-temperature solution method. It exhibits complicated interpenetrating 3D B-O frameworks composed of the functional building block (FBB) [B₈O₁₆]. The UV-vis-NIR diffuse reflectance spectroscopy shows that it has a deep-ultraviolet (DUV) cutoff edge (<200 nm). The relationship between the structures and optical properties was uncovered by theoretical calculations. By the first-principles calculation, the birefringence is estimated to be 0.07 at 1064 nm. The response electron distribution anisotropy (REDA) analysis indicates that the [BO₃] units contribute mainly to the generation of the moderate birefringence.

Sr3B14O24: a new borate with a [B14O30] fundamental building block and an unwonted 2D double layer

A new alkaline-earth metal borate, Sr₃B₁₄O₂₄, was successfully synthesized by a high-temperature solution method. It crystallizes in the monoclinic space group P2₁/c (no. 14) and features a fundamental building block (FBB) [B₁₄O₃₀] which is composed of eight [BO₃] and six [BO₄] units. The FBBs further condense to form an unwonted infinite 2D double layer extended in the bc plane. The UV-Vis-NIR diffuse reflectance spectrum shows that the cutoff edge of Sr₃B₁₄O₂₄ is less than 200 nm, which indicates its potential use in the deep UV region. In addition, the first principles theoretical study was carried out to better understand the relationship between the structure and performance.

A new acentric borate-nitrate Cs3B8O13(NO3) with interpenetrating porous 3D covalent and ionic lattices

A new acentric borate-nitrate Cs3B8O13(NO3) was synthesized by a molten salt method which consists of interpenetrating porous 3D covalent [B8O13]∞ and ionic [(NO3)Cs3]∞ lattices. It shows low ultraviolet cut-off edge (202 nm) and phase-matching second harmonic generation (SHG) intensity (0.7 KDP @1064 nm). First principles calculations showed that the main source of SHG is the cooperation of the B-O and [NO3]- groups.

Research and Development of Zincoborates: Crystal Growth, Structural Chemistry and Physicochemical Properties

Borates have been regarded as a rich source of functional materials due to their diverse structures and wide applications. Therein, zincobrates have aroused intensive interest owing to the effective structural and functional regulation effects of the strong-bonded zinc cations. In recent decades, numerous zincoborates with special crystal structures were obtained, such as Cs₃Zn₆B₉O₂₁ and AZn₂BO₃X₂ (A = Na, K, Rb, NH₄; X = Cl, Br) series with KBe₂BO₃F₂-type layered structures were designed via substituting Be with Zn atoms, providing a feasible strategy to design promising non-linear optical materials; KZnB₃O₆ and Ba₄Na₂Zn₄(B₃O₆)₂(B₁₂O₂₄) with novel edge-sharing [BO₄]^5- tetrahedra were obtained under atmospheric pressure conditions, indicating that extreme conditions such as high pressure are not essential to obtain edge-sharing [BO₄]^5--containing borates; Ba₄K₂Zn₅(B₃O₆)₃(B₉O₁₉) and Ba₂KZn₃(B₃O₆)(B₆O₁₃) comprise two kinds of isolated polyborate anionic groups in one borate structure, which is rarely found in borates. Besides, many zincoborates emerged with particular physicochemical properties; for instance, Bi₂ZnOB₂O₆ and BaZnBO₃F are promising non-linear optical (NLO) materials; Zn₄B₆O₁₃ and KZnB₃O₆ possess anomalous thermal expansion properties, etc. In this review, the synthesis, crystal structure features and properties of representative zincoborates are summarized, which could provide significant guidance for the exploration and design of new zincoborates with special structures and excellent performance.

Ba2ZnSc(BO3)3and Ba4Zn5Sc2(BO3)8: first examples of borates in the Zn–Sc–B–O system featuring special structure configurations

First examples in the Zn–Sc–B–O system featuring a special Zn/Sc–O configuration ([Zn₂(BO₃)₆]¹⁴⁻cluster, lowest-coordinated ScO₅polyhedra, and coexistence of ZnO₄and ZnO₆units).

Structure and Properties of Sodium Enneaborate, Na2[B8O11(OH)4]·B(OH)3·2H2O

Millions of tons of sodium borates are used annually by global industries in diverse applications important to modern society. The Na₂O-B₂O₃-H₂O phase diagram in the 0-100 °C temperature range contains 13 unique hydrated crystalline sodium borates, including five important industrial products. Structures were previously reported for each of these except for that having the highest boron content, known as sodium enneaborate, Na₄B₁₈O₂₉·11H₂O or 2Na₂O·9B₂O₃·11H₂O (1). Here we report the single-crystal structure of 1, revealing the structural formula Na₂[B₈O₁₁(OH)₄]·B(OH)₃·2H₂O, and describe some of its properties and relationships to other sodium borates. The structure of 1 features linear polyborate chains composed of the repeating [B₈O₁₁(OH)₄]^2- fundamental building blocks with interstitial water and boric acid molecules integrated by extensive H bonding. Interstitial sodium cations occur in groups of four with interatomic distances of 3.7830(6) and 3.7932(8) Å. Upon heating, 1 initially becomes amorphous and then crystallizes as α-Na₂B₈O₁₃ along with amorphous B₂O₃. Notably, α-Na₂B₈O₁₃ contains octaborate fundamental building blocks that are topologically equivalent to those in 1. Compound 1 crystallizes in the monoclinic space group P2₁/n with a = 10.2130(8) Å, b = 12.940(1) Å, c = 12.457(1) Å, β = 93.070(2)°, V = 1644.0(2) ų, and Z = 2.

Two New Copper Borates with Mesoscale Cubic Supramolecular Cages Assembled from {Cu4 @B20 } Clusters

Two new copper borates, namely H₆ [(μ₄ -O)Cu₄ @B₂₀ O₃₂ (OH)₈ ]⋅25 H₂ O (1) and H₆ [(μ₄ -O)Cu₄ @B₂₀ O₃₂ (OH)₈ ]⋅34 H₂ O⋅8 H₃ BO₃ (2), with 3D supramolecular framework have been made under solvothermal conditions, which built by novel cubic supramolecular cages with mesoscale cavities via the H-bondings. Interestingly, the cage is assembled by [(μ₄ -O)Cu₄ @B₂₀ O₃₂ (OH)₈ ] ({Cu₄ @B₂₀ }) cluster units with different point-group symmetry. Owing to extra H₃ BO₃ molecules participated in building the supramolecular framework, 2 has a larger cubic cage size and higher non-framework volume, leading to the cage size extended to mesoporous size set as a version of ''1 plus".

Two deep-ultraviolet nonlinear optical alkaline-earth metal borates based on different types of oxoboron clusters

Two non-centrosymmetric alkaline-earth metal borates were synthesized, showing the layered structures constructed from different oxoboron clusters and potentially new candidates for deep-UV NLO materials.