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A new SHG material, Ba3[Al(PO4)3], has been rationally designed by expanding the anionic condensation design strategy from atom-sharing to anionic-group-sharing. As the first Ba3[B(PO4)3]-type acentric phosphate, Ba3[Al(PO4)3] is characterized by moderate second-order optical nonlinearity, beneficial type I phase-matching behavior, deep-UV transparency and high thermal stability, favourable for practical applications. [ABSTRACT FROM AUTHOR]

Large birefringence (Δn = 0.277 at 546 nm) and strong second-harmonic generation (SHG) intensity (4.3 × KDP) achieved a remarkable balance in a potential ultraviolet nonlinear optical crystal: 2(C3H7N6)+·2Cl−·H2O. Theoretical calculations showed that planar benzene-like π-conjugated [C3N6] groups had important optical properties. [ABSTRACT FROM AUTHOR]

We report a new strongly birefringent material, [Al(H2O)6](IO3)2(NO3) (AINO). Based on a detailed analysis, we concluded that its enhanced birefringence (0.253 at 546 nm) predominantly resulted from a synergy of the effects of its (NO3)− and (IO3)− functional motifs, combined with an equally important and indispensable optimal arrangement of these two groups in the structure. This work has provided insight for discovering new birefringent materials. [ABSTRACT FROM AUTHOR]

The first alkali‐metal vanadium iodate fluoride, CsVO2F(IO3), with a novel 3D anionic framework, has been rationally designed and hydrothermally synthesized. The 3D [VO2F(IO3)]− framework in CsVO2F(IO3) is built from 0D Λ‐shaped cis‐[VO3F(IO3)2]4− polyanions via corner‐sharing of oxo anions and bridging of the iodate groups. CsVO2F(IO3) displays both a strong second‐harmonic generation (SHG) 1.1 times as strong as KTiOPO4 (KTP) under 2.05 μm laser radiation and high laser‐induced damage threshold (LIDT) of 107.9 MW cm−2. This work provides a new route to design SHG crystals with stable 3D anionic structures from low‐dimensional structural building units. [ABSTRACT FROM AUTHOR]

The first divalent-metal iodate-phosphate, Pb2(IO3)(PO4), has been prepared via the strategy of introducing (IO3)− into phosphate. The structure features a unique 3D network where [Pb(IO3)]∞+ and [Pb(PO4)]∞− layers are alternatively interconnected. The birefringence of Pb2(IO3)(PO4) is greatly increased to 0.060 at 1064 nm. [ABSTRACT FROM AUTHOR]

A cesium bismuth germanate, Cs2Bi2O(Ge2O7) (CBGO), was synthesized by a traditional high‐temperature solid‐state reaction. Its structure features a 3D network composed of a 1D chains composed of Bi2O8 dimers that are further bridged by Ge2O7 dimers, forming tunnels of seven member rings (MRs) that are filled by the Cs+ cations. CBGO exhibits extraordinary larger second harmonic generation (SHG) response of about 13.7 times that of KDP (KH2PO4) under 1064 nm laser radiation and 1.1 times that of KTP (KTiOPO4) under 2.05 μm laser radiation, which is the highest among all of the metal germanates reported so far. CBGO possesses a moderate birefringence (0.073 at 1064 nm) and is phase matchable. Furthermore, CBGO melts congruently and exhibits high thermal stability. [ABSTRACT FROM AUTHOR]

The first examples of rare‐earth polyiodates, namely, REI5O14 (RE=Y and Gd), have been prepared by hydrothermal reactions of RE2O3 and H5IO6 in H3PO4 (≥85 wt % in H2O), with extremely high yields (>95 %). They crystalize in the polar space group Cm and feature a brand‐new semicircle‐shaped [I5O14]3− pentameric polyiodate anion composed of two IO3 and three IO4 polyhedra. Remarkably, both compounds exhibit very large second‐harmonic generation (SHG) signals (14× and 15×KH2PO4 (KDP) upon 1064 nm laser radiation for Y and Gd compounds, respectively). Our work shows that the hydrothermal reaction in a phosphoric acid medium facilitates the formation of rare‐earth polyiodates. [ABSTRACT FROM AUTHOR]

By using hydrofluoric acid as a solubilizer, the first alkali-metal niobium iodate and an alkali-earth metal niobium iodate, i.e. (H3O)HCs2Nb(IO3)9 and SrNbO(IO3)5, have been obtained. An obvious cation-controlled polarity shift is observed in the Ae/A-Nb5+-IO3 system. (H3O)HCs2Nb(IO3)9 gives a strong second harmonic generation (SHG) signal about 6 times that of KH2PO4 (KDP), making it a promising nonlinear optical (NLO) material. [ABSTRACT FROM AUTHOR]

The first examples of bismuth fluoride selenites with d0‐TM/TeVI polyhedrons, namely, Bi4TiO2F4(SeO3)4 (1), Bi4NbO3F3(SeO3)4 (2), Bi4TeO4F2(TeO3)2(SeO3)2 (3), Bi2F2(MoO4)(SeO3) (4) and Bi2ZrO2F2(SeO3)2 (5) have been successfully synthesized under hydrothermal reactions by aliovalent substitution. The five new compounds feature three different types of structures. Compounds 1–3, containing TiIV, NbV and TeVI respectively, are isostructural, exhibiting a new 3D framework composed of a 3D bismuth oxyfluoride architecture, with intersecting tunnels occupied by d0‐TM/TeVI octahedrons and selenite/tellurite groups. Interestingly, compound Bi4TeO4F2(TeO3)2(SeO3)2 (3) is the first structure containing SeIV and mixed‐valent TeIV/TeVI cations simultaneously. Compound 4 features a new 3D structure formed by a 3D bismuth oxyfluoride network with MoO4 tetrahedrons and selenites groups imbedded in the 1D tunnels. Compound 5 displays a novel pillar‐layered 3D open framework, consisting of 2D bismuth oxide layers bridged by the [ZrO2F2(SeO3)2]6− polyanions. Theoretical calculations revealed that the five compounds displayed very strong birefringence. The birefringence values of compounds 1–3, especially, are above 0.19 at 1064 nm, which are larger than the mineral calcite. Based on the structure and property analysis, it was found that the asymmetric SeO3 groups (and TeO3 in compound 3) displayed the largest anisotropy, compared with the bismuth cations and the d0‐TM/Te polyhedra, which is beneficial to the birefringence. Birefringence: The first examples of bismuth fluoride selenites with d0‐TM/TeVI polyhedra, have been successfully synthesized under hydrothermal reactions by aliovalent substitution. Theoretical calculations revealed that the isostructural compounds of Bi4TiO2F4(SeO3)4, Bi4NbO3F3(SeO3)4 and Bi4TeO4F2(TeO3)2(SeO3)2 displayed very strong birefringence values, which are larger than the mineral calcite. [ABSTRACT FROM AUTHOR]