An effective pathway to design and synthesize UV birefringent crystalsviarational assembly of π-conjugated [CO₃]²⁻and [NO₃]⁻triangles

Abstract

Planar MO3 (M=B, C, N) units have frequently been considered as the important structural components of novel birefringent crystal materials. An efficient approach for creating new functional crystals is to...

Two UV optical crystals with strong optical anisotropy, large band gaps and an α-BBO type structure

“…2a and b, a two-stage transition occurs near 300 nm in the UV absorption spectra of compounds 1 and 2 . Similar absorptions have been found in recently reported UV absorptions of other structures, such as Y 5 (C 3 N 3 O 3 )(OH) 12 , 33 Na 3 Rb 6 (CO 3 ) 3 (NO3) 2 Cl·6H 2 O, 34 and RE(H 2 C 3 N 3 O 3 ) 2 ·(OH)· x H 2 O (RE = La, Y and Gd). 14 Although these compounds exhibit another absorption peak near 300 nm, the authors did not analyze these in detail.…”

Na3K6(CO3)3(NO3)2X·6H2O (X = NO3, Cl, Br): Exploring High-Performance UV Birefringent Crystals Induced by Coplanar π-Conjugated CO3 and NO3 Groups

“…Therefore, the Na atom has the potential to guide the MO 3 anionic groups to arrange in coplanar mode. This has been confirmed by the findings of compounds Rb 2 Na(NO 3 ) 3 , 54 NaK 2 (HCO 3 )(CO 3 )•2H 2 O, 55 NaRb 2 (HCO 3 )(CO 3 )•2H 2 O, 56 Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 Cl• 6H 2 O, 35 and Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 Br•6H 2 O, 36 in which Na-centered polyhedra provide the equatorial O atoms. Meanwhile, other alkali metals, like K, Rb, and Cs cations with a large atomic size, usually have more coordination numbers, which can increase structural diversity.…”

“…These differences may have originated from the influence of second cations (namely, Cs in CsSrCO 3 F, A in ASrCO 3 F (A = K, Rb)), which has been proved by many works. 25,36,50,69 There is no second cation in Sr(OH)NO 3 and Ba(OH)NO 3 , so the large Sr and Ba cations only have three equatorial O atoms.…”

“…Meanwhile, the anisotropic polarization of CO 3 and NO 3 is superior to that of BO 3 , and they can be also able to penetrate the UV or even deep-UV region; so CO 3 and NO 3 are more suitable for the construction of birefringent materials. − This motivates our interest in finding new UV birefringent crystals in the carbonate nitrate family. Based on a survey of the Inorganic Crystal Structure Database (ICSD with the version of 5.1.0., the last release of ICSD-2023–02) and recent publications, there are 12 synthetic members reported in the carbonate nitrate family, including (Tl 0.85 Cr 0.15 )­Sr 4 Cu 2 (CO 3 ) 0.5 (NO 3 ) 0.5 O 7 , [Co­(CO 3 )­(NH 3 ) 4 (NO 3 )] 2 ·H 2 O, [Pt­(NH 3 ) 2 ] 4 (CO 3 ) 2 (NO 3 ) 4 ·3H 2 O, Co­(CO 3 )­(NH 3 ) 4 NO 3 , Co­(NH 3 ) 5 (CO 3 )­NO 3 ·H 2 O, Ca 5 (UO 2 (CO 3 ) 3 ) 2 (NO 3 ) 2 ·10H 2 O, Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 Cl·6H 2 O, Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 Br·6H 2 O, Pb 6 O 4 (OH)­(NO 3 )­(CO 3 ), PbTiO 2 (CO 3 ) 0.3 (NO 3 ) 0.35 (OH), (NH 3 ) 6 Rh 2 (OH) 2 (CO 3 )­(NO 3 ) 2 ·H 2 O, and (NH 3 ) 6 Co 2 (OH) 2 (CO 3 )­(NO 3 ) 2 ·H 2 O . A few of them have systematically reported their optical and physicochemical properties.…”

AX·(H2SeO3)n (A = K, Cs; X = Cl, Br; n = 1, 2): A Series of Ionic Cocrystals as Promising UV Birefringent Materials with Large Birefringence and Wide Band Gap

“…To tackle this challenge, we chose selenite system as the main birefringent material source and used alkali metal halide to adjust the crystal structure and band gap of selenite compounds. The reasons for choosing alkali metal halide are as follows: (1) alkali metal cations can broaden the band gap and increase UV transparency owing to the lack of d–d or f–f electronic transitions; , (2) halogen anions possess distinctive electronegativity, ionic radius, coordination capability, and polarizability, which could make the UV cutoff edges blue-shift and increase structural distortion. , So, alkali metal halide is beneficial for broadening the band gap of selenite. The next problem is how to achieve the combination of above functional units to get new alkali metal halide selenite.…”