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

Abstract

A new hydroxyl rubidium borate, RbB11O16(OH)2, has been obtained in the sealed system. Its structure consists of a two‐dimensional layered anionic framework, which is composed of the fundamental building block, [B11O18(OH)2]5−. Detailed structural comparison with other hydroxyl rubidium borates indicates that RbB11O16(OH)2 is the first hydroxyl rubidium borate with a B−O layered structure. First‐principle theoretical studies have been conducted to help understand the electronic structure and its optical properties, and the results suggest that RbB11O16(OH)2 can be regarded as the potential birefringent crystal.

Extending Unique 1D Double-Chains to 2D Layers with Birefringent Gain by Introducing a Hydroxyl Group

“…So, the FBB [B 11 O 23 (OH) 3 ] can be described as 11: [⟨2Δ3 T ⟩ 8 + ⟨Δ4 T ⟩ 8 + ⟨Δ⟩] and is further condensed to 2D thick layers by sharing four O atoms. (2) NH 4 B 11 O 16 (OH) 2 , KB 11 O 16 (OH) 2 , RbB 11 O 16 (OH) 2 , and CsB 11 O 16 (OH) 2 are isostructural and possess the same FBB, − [B 11 O 18 (OH) 2 ], with the notation 11: [⟨3Δ⟩ + ⟨4Δ T ⟩ 8 + ⟨3Δ⟩]. Two BO 3 triangles and one BO 2 (OH) unit are interconnected through shared vertex O atoms, forming a three-membered ring B 3 O 5 (OH) unit.…”

CsB3O4(OH)2: a new deep-ultraviolet birefringent crystal with [B3O4(OH)2] anionic group

“…The obtained birefringence value from this method can be compared with other previous reported hydroxyborates, including CaH(BO 3 ) (0.103@546.1 nm), 27 Be 2 (BO 3 )(OH) (0.074@546.1 nm), 47 Sr 2 B 11 O 16 (OH) 5 ·H 2 O (0.069@546.1 nm), 48 CsB 7 O 10 (OH) 2 (0.08@1064 nm), 49 and RbB 11 O 16 (OH) 2 (0.09@1064 nm). 50 It is also competitive among other DUV birefringent materials, such as Li 2 Na 2 B 2 O 5 9 (0.097@546 nm), RbB 3 O 4 F 2 (0.09@1064 nm), 30 SrB 4 OF 2 (0.089@1064 nm), 51 Na 2 Gd(CO 3 )F 3 (0.084@1064 nm), 52 NaB 6 O 9 F 2 (0.08@1064 nm), 53 and NaMgBe 2 (BO 3 ) 2 F (0.078@589 nm). 54 Thus, it indicates that the birefringence of CBOH can meet the application requirements in the DUV regions.…”