Sb₆O₇(SO₄)₂: A Promising Ultraviolet Nonlinear Optical Material with an Enhanced Second‐Harmonic‐Generation Response Activated by Sb^III Lone‐Pair Stereoactivity

Abstract

The stereochemical activity of lone pairs (SCALP) in a cation favors the formation of acentric materials and can enhance the second‐harmonic‐generation (SHG) response and/or the birefringence. By introducing functional SbIII into sulfates, an anhydrous sulfate of Sb6O7(SO4)2 (1) is explored. Sb3+ cations are in seesaw configurations and in‐phase aligned in a 3D asymmetric dense structure. Compound 1 exhibits an enhanced phase‐matching SHG response, a moderate birefringence, a wide transparency window, and considerable environmental stabilities, which result in it being a promising UV nonlinear optical (NLO) material. Theoretical studies reveal that the stereoactive lone pairs on Sb3+ cations make the predominant contribution to the SHG effect. This work will attract more interest from scientists for research into SCALP‐cation‐based NLO materials.

Two Short-Wave UV Antimony(III) Sulfates Exhibiting Large Birefringence

“…Similarly, the distinctive absorption bands with Sb–O in Ca 2 Sb 2 O­(SO 4 ) 4 are located at 673, 618, 593, and 454 cm –1 . The identified characteristic peaks can be confirmed by previous literature. ,,− …”

Sb4O3(TeO3)2(HSO4)(OH): An Antimony Tellurite Sulfate Exhibiting Large Optical Anisotropy Activated by Lone Pair Stereoactivity

“…The result shows that the calculated birefringence of Sb 4 O 3 (TeO 3 ) 2 (HSO 4 )­(OH) is 0.137 at 546 nm. The value is larger than those of many Sb-based birefringent crystals. − More importantly, the value exceeds those of the most reported metal sulfate tellurites, In 2 (TeO 3 )­(SO 4 )­(OH) 2 (H 2 O) (0.0561 @ 1064 nm), Ga 2 (TeO 3 )­(SO 4 )­(OH) 2 (0.1029 @ 1064 nm), Y 3 (TeO 3 ) 2 (SO 4 ) 2 (OH)­(H 2 O) (0.092 @ 532 nm), and Zn 4 (Te 3 O 7 ) 2 (SO 4 ) 2 (H 2 O) (0.084 @ 1064 nm) is lower than that of Hg 3 (Te 3 O 8 )­(SO 4 ) (0.184 @ 532/0.166 @ 1064 nm), in which, in addition to the contribution of the SCALP effect of the Te 4+ cation, the large deformability of Hg 2+ also further promotes the birefringence. Therefore, it is speculated that the introduction of the “extra” SCALP cation Sb 3+ may further enhance the birefringence of sulfate tellurites, and the optical property of Sb 4 O 3 (TeO 3 ) 2 (HSO 4 )­(OH) may be determined by the synergistic effect of the SCALP effect of both Sb 3+ and Te 4+ cations.…”

Chiral amino acid-templated tin fluorides tailoring nonlinear optical properties, birefringence, and photoluminescence

“…In general, NCS compounds containing stereochemically active lone pair cations are more likely to exhibit second harmonic generation (SHG) response 16–18 and significant birefringence. 19,20 However, a critical issue concerns the stability of Sn( ii ) ions, which are prone to disproportionation, leading to products with Sn(0) and Sn( iv ) oxidation states.…”

“…[12][13][14] Chiral templates inherently belong to the NCS crystal system, allowing them to exhibit NLO characteristics and hold promise for optical applications. 15 In general, NCS compounds containing stereochemically active lone pair cations are more likely to exhibit second har-monic generation (SHG) response [16][17][18] and significant birefringence. 19,20 However, a critical issue concerns the stability of Sn(II) ions, which are prone to disproportionation, leading to products with Sn(0) and Sn(IV) oxidation states.…”