A₂B₆O₉F₂(A = NH₄, K): new members of A₂B₆O₉F₂family with deep-UV cutoff edges and moderate birefringence

Abstract

The fluorooxoborate A2B6O9F2 family (A = alkali metal) has attracted much attention because of its diverse structures and properties. Herein, two new members of this family, (NH4)2B6O9F2 and K2B6O9F2, have...

NaRbB10O14(OH)4 and Na3CsB10O16(OH)2: Two Cases of Hydroxyborates with [B5Om(OH)n] Units and Deep Ultraviolet Cutoff Edges

“…However, the terminal oxygen atoms with dangling bonds are not conducive to DUV transparency, which is one of the most essential concerns for UV/DUV materials. For example, the dangling bonds of β-Rb 2 Al 2 B 2 O 7 , BaAlBO 3 F 2 , and CsAlB 3 O 6 F are removed by introducing [AlO 4 ] and [AlO m F n ] ( m + n = 4, 5, 6) units, and all of them possess DUV cutoff edges. − Additionally, a part of terminal O atoms in the [BO 4 ] unit can be swapped by large electronegative F atoms to generate [BO 4– x F x ] ( x = 1, 2, 3, 4) units resulting in high-performing fluorooxoborates with DUV absorption edges, − such as MB 4 O 6 F (M = NH 4 , Na, Rb, Cs), − MB 5 O 7 F 3 (M = Mg, Ca, Sr), − Ba 3 Mg 3 (BO 3 ) 3 F 3, M 2 B 6 O 9 F 2 (M = Li, Na, NH 4 , K), ,− PbB 5 O 8 F, etc. Especially, the dangling bonds of terminal O atoms of [BO 3 ] and [BO 4 ] in [BO 3– x (OH) x ] ( x = 1, 2, 3) and [BO 4– x (OH) x ] ( x = 1, 2, 3, 4) groups can be eliminated by introducing the [OH] unit − and also possible enhance the energy gap, hyperpolarizability, and polarizability anisotropy. − It is worth noting that many hydroxyl borates are excellent DUV optical crystals, such as AEB 8 O 15 H 4 (AE = Ca, Sr), Ba 2 [B 4 O 7 (OH) 2 ], Li 2 CsB 7 O 10 (OH) 4 , β -A 2 [B 5 O 8 (OH)] 2 [B­(OH) 3 ]·H 2 O (A = Ca, Ba), Zn 2 BO 3 (OH), Ba 2 B 13 O 19 (OH) 5 ·5H 2 O, , etc.…”

Two Short-Wave UV Beryllium Selenites Exhibiting Diverse Optical Properties Stemming from Functional Group Arrangements

“…Through exploring the structure–property relationship of a large number of NLO crystals, some effective strategies for improving SHG response have been suggested, such as introducing π-delocalized anionic groups ([BO 3 ] 3– , [CO 3 ] 2– , [NO 3 ] − , etc. ), − introducing transition-metal (TM) cations with second-order Jahn–Teller (SOJT) distortions (Zr 4+ , Nb 5+ , Mo 6+ , etc. ), − and introducing stereochemically active lone pair (SCALP) cations (Se 4+ , Sn 2+ , Te 4+ , etc.…”

Low temperature molten salt synthesis of noncentrosymmetric (NH4)3SbF3(NO3)3and centrosymmetric (NH4)3SbF4(NO3)2

“…11,12 It has been found that the reasonable combination of different asymmetric chromo-phores is an effective tactic for the synthesis of NLO materials, which is conducive to the generation of large second harmonic generation (SHG) response. 13,14 Common asymmetric chromophores include (1) planar π-conjugated anions, such as BO 3 3− , CO 3 2− , and NO 3 − ; [15][16][17] (2) distorted polyhedra of d 0 and d 10 transition metal ions, such as Ti 4+ , Mo 6+ , Zn 2+ , and Hg 2+ ; [18][19][20][21][22] (3) lone pair electron cations with stereochemical activity, such as Pb 2+ and Bi 3+ . [23][24][25] In comparison to planar π-conjugated anionic ions, the BO 3 3− system is relatively mature at present, and numerous splendid NLO crystals have been obtained, such as β-BaB 2 O 4 (β-BBO), 26 LiB 3 O 5 (LBO), 27 and KBe 2 BO 3 F 2 (KBBF).…”