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Trigonal planar units with large polarizability anisotropy and high physicochemical stability are ideal structural units for exploring nonlinear optical (NLO) materials. Integrating the merits of two types of triangular‐like moieties, a family of second‐order NLO‐active hybrid halides, MATX (X = Cl (1), Br (2), and I (3)), are achieved. MATX crystallizes in a nonpolar space group of P6¯$P\overline 6 $2c but exhibits the optimal spatial arrangement and superior NLO performance. The low coordination planar trigonal AgX3 units enable segregation in layers of the three‐winged propeller‐like Me3TPA units. All of the layers are packed in a perfect parallel fashion, making the functional materials exhibit superior NLO performances, including the phase matchable behavior with strong SHG responses (6.2/1, 6.5/2, and 7.6/3 times that of potassium dihydrogen phosphate), large birefringence (0.232/1, 0.252/2 and 0.260/3 at 1064 nm), high laser damage threshold, wide transparent window, and easiness of crystal growth. The first‐principles calculations reveal that the coexistence of strong linear and nonlinear optical properties are ascribed to the synergistic effect of the trigonal moieties. This study points out a useful path for the rational design of excellent NLO materials. [ABSTRACT FROM AUTHOR]

Through systematic experiments, two novel mercury iodate sulfates, namely, Hg2(IO3)2(SO4)(H2O) and Hg2(IO3)2(SO4) were obtained. They crystallize in monoclinic space group C2 and C2/c, respectively. Hg2(IO3)2(SO4)(H2O) exhibits the [Hg(IO3)]+ polar cationic layer inherited from Hg(IO3)2 and the three‐dimensional (3D) framework inherited from HgSO4. This enables Hg2(IO3)2(SO4)(H2O) to generate a strong second harmonic generation (SHG) response of 6 times that of KH2PO4 (KDP). The structure of Hg2(IO3)2(SO4) is very similar to that of Hg2(IO3)2(SO4)(H2O), and they can be transformed into each other. Hg2(IO3)2(SO4)(H2O) shows a large optical band gap of 3.98 eV and a high dehydration temperature of 250 °C. This study indicates that by reasonable design, the introduction of multiple functional groups into a compound may combine their advantages to achieve good overall optical performance. [ABSTRACT FROM AUTHOR]

• NaMoO 3 (IO 3) is the first example of molybdenum(VI) iodate with 1D chain-like structure featuring a large birefringence (0.208@1064 nm). • Both 1D [MoO 3 (IO 3)]- anionic chain in NaMoO 3 (IO 3) and 3D [MoO 3 (IO 3)]- anionic framework in γ-KMoO 3 (IO 3) are assembled from 0D Λ-shaped cis -MoO 4 (IO 3) 2 units. • The polar 3D γ-KMoO 3 (IO 3) exhibits the largest SHG response (12 × KDP) among AMoO 3 (IO 3) family as well as a high LIDT value (52 × AGS). [Display omitted] Herein, we reported two alkali metal molybdenum(VI) iodates, namely, NaMoO 3 (IO 3) and γ-KMoO 3 (IO 3) with 1D and 3D [MoO 3 (IO 3)]− anionic architectures, respectively. The novel 1D chain in NaMoO 3 (IO 3) and the 3D network in γ-KMoO 3 (IO 3) are constructed by the 0D Λ-shaped cis -[MoO 4 (IO 3) 2 ]4− building units interconnected by bridging IO 3 − anions as well as the corner-sharing of oxo anions. Importantly, the polar γ-KMoO 3 (IO 3) exhibits a very large second-harmonic generation (SHG) effect of 12 × KH 2 PO 4 (KDP) under 1064 nm laser radiation, a high laser-Induced damage threshold value (52 × AgGaS 2), and a moderate birefringence of 0.087@1064 nm, whereas the centrosymmetric NaMoO 3 (IO 3) has a large birefringence of 0.208@1064 nm. This study further proves the useful route of exploring promising optical materials via assembling the 0D basic building units into higher dimensional anionic architectures. [ABSTRACT FROM AUTHOR]