The transformation of a zero-dimensional cluster into a one-dimensional chain structure achieving a dramatically enhanced birefringence in tin(ii)-based oxalates

Abstract

Developing new birefringent materials with large optical anisotropy is extremely urgent attributed to the fantastic spur of laser science and technology. Here, two tin(Ⅱ)-based oxalates, K2Sn(C2O4)2•H2O and K2Sn2(C2O4)2F2•H2O were successfully...

C(NH2)3Cd(C2O4)Cl(H2O)·H2O and BaCd(C2O4)1.5Cl(H2O)2: Two Oxalate Chlorides Obtained by Chemical Scissors Strategy Exhibiting Low-Dimensional Structural Networks and Balanced Overall Optical Properties

“…Compared to other oxalate halides, C­(NH 2 ) 3 Cd­(C 2 O 4 )­Cl­(H 2 O)·H 2 O show smaller band gaps . Without the influence of C­(NH 2 ) 3 + , BaCd­(C 2 O 4 ) 1.5 Cl­(H 2 O) 2 exhibits a larger band gap, which is also larger than K 2 Sb 2 (C 2 O 4 )­F 6 (4.27 eV), [C­(NH 2 ) 3 ]­Sb­(C 2 O 4 )­F 2 ·H 2 O (4.09 eV), NH 4 Sb 2 (C 2 O 4 )­F 5 (3.85 eV), Rb 2 SbC 2 O 4 Cl 3 (3.74 eV), (CN 4 H 7 )­SbC 2 O 4 F 2 (H 2 O) 0.5 (3.44 eV), and K 2 Sn 2 (C 2 O 4 ) 2 F 2 ·H 2 O (3.21 eV). − The band gaps of the A-M-C 2 O 4 -X (A = monovalent cationic or alkaline earth metals; X = F, Cl, Br, I) family are collected (Figure ), which reveals that BaCd­(C 2 O 4 ) 1.5 Cl­(H 2 O) 2 shows the largest band gap among them. IR spectra of C­(NH 2 ) 3 Cd­(C 2 O 4 )­Cl­(H 2 O)·H 2 O and BaCd­(C 2 O 4 ) 1.5 Cl­(H 2 O) 2 are rendered (Figure S7).…”

Na4Sn4(C2O4)3F6 and NaSnC2O4F·H2O: two tin(ii) fluoride oxalates display large birefringence

“…The results indicate that the calculated birefringence (Δ n = n z − n x ) is 0.167@546 nm for Na 4 Sn 4 (C 2 O 4 ) 3 F 6 and 0.192@546 nm for NaSnC 2 O 4 F·H 2 O, which aligns well with the experimental values. And Two compounds, especially NaSnC 2 O 4 F·H 2 O, exhibit large birefringence superior to conventional birefringent crystals, some Sn 2+ -based compounds and oxalate crystals, such as α-BaB 2 O 4 (0.122@546 nm), 8 MgF 2 (0.012@532 nm), 7 LiNbO 3 (0.074@546 nm), 40 CaCO 3 (0.172@532 nm), 9 β-SnB 4 O 7 (0.078@1064 nm), 41 Sn 2 B 5 O 9 Cl (0.168@546 nm), 26 Sn 2 PO 4 X (X = F, Cl) (0.103, 0.162@546 nm @546 nm), 42 α-SnF 2 (0.177@546 nm), 19 Rb 3 SnCl 5 (0.046@546 nm), 43 RbSn 2 Cl 5 (0.123@546 nm), 44 Cs 2 C 2 O 4 (0.022@1064 nm), 44 K 2 Sb 2 (C 2 O 4 )F 6 (0.097@546 nm), 28 K 2 Sn(C 2 O 4 ) 2 ·H 2 O(0.103@546 nm) 22 and NH 4 Sb 2 (C 2 O 4 )F 5 (0.111@546 nm). 45…”

“…20 A detailed analysis reveals that Sn 2+ -based compounds have distinctive characteristics. Firstly, Sn 2+ cation has a variety of coordination modes, tri-coordination like SnO 3 in Sn 14 O 11 Br 6 , 21 quad-coordination like SnO 4 in K 2 Sn(C 2 O 4 ) 2 ·H 2 O, 22 penta-coordination like SnO 2 Cl 3 in Rb 3 Sn 2 (SO 4 ) 2 Cl 3 , 23 hexa-coordination like Sn 2 F 4 in RbSnF 2 NO 3 24 and so on. The rich coordination environment of Sn 2+ offers the opportunity to construct diverse crystal structures.…”

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 search for new birefringent materials, it is necessary to introduce birefringence-active units with larger optical anisotropy. 10,11 Stereochemical active lone pair (SCALP) cations (Pb 2+ , Se 4+ , Bi 3+ , Sb 3+ , Sn 2+ , etc.) 12−15 can form distorted polyhedra with large optical anisotropy because the presence of lone pairs can impose the repulsive interaction with anions, so the SCALP cations are considered to be one type of attractive birefringence-active units.…”

“…From the structure–property relationship, the large birefringence of a crystal relies on the large polarizability anisotropy of structural building units. To search for new birefringent materials, it is necessary to introduce birefringence-active units with larger optical anisotropy. , Stereochemical active lone pair (SCALP) cations (Pb 2+ , Se 4+ , Bi 3+ , Sb 3+ , Sn 2+ , etc. ) − can form distorted polyhedra with large optical anisotropy because the presence of lone pairs can impose the repulsive interaction with anions, so the SCALP cations are considered to be one type of attractive birefringence-active units. − Benefiting from the distorted polyhedra with SCALP cations, compounds like Sn 2 B 5 O 9 Cl (0.171 at 546 nm), SbB 3 O 6 (0.318 at 546 nm), α-SnF 2 (0.191 at 546 nm), LiGaF 2 (IO 3 ) 2 (0.206 at 532 nm), SrZnSnSe 4 (0.29 at 1240 nm), Cd 2 Nb 2 Te 4 O 15 (0.13 at 546 nm), K 2 Sb­(P 2 O 7 )F (0.162 at 546 nm), and Rb 2 Sn 2 F 5 Cl (0.31 at 532 nm) have remarkable birefringence.…”