LiMg(IO3)3: an excellent SHG material designed by single-site aliovalent substitution

SbO(OH)2(IO3): The First Polar Sb5+-Iodate with a Strong Second-Harmonic Generation Response and a Wide Bandgap

Widening the bandgaps while maintaining a strong second harmonic generation response has always been a research hotspot in the field of nonlinear optical iodate materials. A strategy involving covalent bonding is proposed that leverages the high valent later main group cation to construct iodates with predominantly covalent interactions. By using BiO(IO3) as a template, the first Sb5+-containing polar iodate, SbO(OH)2(IO3) is successfully isolated. The introduction of the two hydroxide anions led to the reduction of layered BiO(IO3) into 1D SbO(OH)2(IO3) in which two corner-sharing SbO4(OH)2 octahedra are further bridged by an iodate group. The covalently bonded [SbO(OH)2]+ chains and the optimal packing fashion of the asymmetric IO3 - groups generate a very strong second harmonic generation signal of 14 times that of KH2PO4. Furthermore, SbO(OH)2(IO3) exhibits a wide bandgap of 4.14 eV and a high laser induced damage threshold [27.9 × AgGaS2, 0.2 × KH2PO4 (10 ns, 10 Hz)].

Ba2Ga2F6(IO3)(PO4): the first fluoride-containing iodate-phosphate with a 1D [Ga2F6(IO3)(PO4)]4- helix chain

Herein, the first F-containing iodate-phosphate, namely Ba2Ga2F6(IO3)(PO4), was prepared via a hydrothermal reaction, in which HPF6 (70 wt% solution in water) was used as the source of both fluoride and phosphate anions for the first time. Ba2Ga2F6(IO3)(PO4) features an unprecedented 1D [Ga2F6(IO3)(PO4)]4- helix chain, composed of a 1D Ga(1)(IO3)O4F chain via the bridging of 0D Ga(2)(PO4)F5. The UV-Vis spectrum shows that Ba2Ga2F6(IO3)(PO4) has a wide bandgap with a short-UV absorption edge (4.35 eV; 253 nm). Birefringence measurement under a polarizing microscope shows that Ba2Ga2F6(IO3)(PO4) displays a moderate birefringence of 0.072@550 nm, which is consistent with the value (0.070@550 nm) obtained by DFT calculations, indicating that Ba2Ga2F6(IO3)(PO4) has potential applications as a short-UV birefringent material. This study highlights the crucial role played by the incorporation of specific functional groups into compounds, shedding light on their contribution to promising inorganic functional materials.

Chromium iodate: the structure and origin of optical second harmonic generation

Iodate crystal materials are some of the important candidates for mid-infrared nonlinear optical (NLO) crystals. Almost all the structures and NLO properties of monometallic iodates have been studied, except for a few difficult to synthesize crystalline phases. In this work, crystalline Cr(IO3)3 was synthesized and its optical properties were studied. Cr(IO3)3 has a strong powder second-harmonic generation (SHG) effect (1.3 × AgGaS2) and a large birefringence (0.24) at 2100 nm. Theoretical calculations indicate that the 3d orbital of Cr3+ is strongly involved in the SHG process, and the contribution of the metal cation centered unit CrO6 to the SHG response is much greater than that of the non-metal cation centered unit IO3. This study provides a new case among the few NLO materials in which the SHG response is dominated by metal cation centered groups.

Anhydrous Aluminum Iodate: Strong Second Harmonic Generation Effect Contributed by Unbonded and Antibonding Orbitals

Exploring materials that balance the second harmonic generation (SHG) effect and laser-induced damage threshold (LIDT) is the frontier of nonlinear optical (NLO) crystal research at present. In this work, the NLO property of anhydrous aluminum iodate is extensively explored and discussed first. It exhibits a strong SHG intensity of 18.3 × KH2PO4 (KDP) and a high-powder LIDT of 1.4 × KDP at 1064 nm. Combining experimental and theoretical studies at the atomic level and electronic levels, it is found that the cations in the structure are replaced by cations with small radius and high valence, enabling the production of materials with large SHG responses. Unbonded and antibonding orbitals play a crucial positive role in the SHG response of the structure, whereas bonding orbitals produce a large negative contribution. This provides a scarce example of materials in which bonding orbitals make significant negative contributions.

From ZnF2 to ZnF2(H2O)4: Partial Substitution Achieves Structural Transformation and Nonlinear Optical Activity while Keeping Short Ultraviolet Cutoff Edge

Exploring nonlinear optical (NLO) materials with short ultraviolet cutoff edges are significant for developing an all-solid-state laser. Here, a noncentrosymmetric zinc fluoride hydrate, ZnF2(H2O)4, was synthesized by a hydrothermal method. It crystallizes in the polar space group of Pca21. The compound consists of the central Zn2+ combined with F- and coordination water to form the [ZnF2(H2O)4] octahedra, and each octahedron is isolated from each other to form a 0-dimensional structure. As an acentric compound, ZnF2(H2O)4 shows a phase-matchable second-harmonic-generation (SHG) activity with an intensity about 0.5 times that of KH2PO4. More attractively, it also shows a short ultraviolet cutoff edge below 200 nm, which is rare in reported halide hydrate systems. Interestingly, from ZnF2 to ZnF2(H2O)4, the partial substitution of the coordinated F atoms by H2O molecules leads to the structural transformation from centric to acentric with SHG activity off to on. Structural analyses, NLO activity, and theoretical calculations are presented in this work.

From NaGa(IO3)3F to NaGa(IO3)2F2 and NaGa(IO3)4: The Effects of Chemical Substitution between F- Anions and IO3- Groups on the Structures and Properties of Gallium Iodates

Introducing F- anions or substituting F- anions with IO3- groups has been proven to be ideal strategies for designing novel noncentrosymmetric (NCS) and polar materials, yet systematic investigation into the effect of F- anions or the substitution of IO3- for F- anions on structures and properties remains rarely explored. Herein, two new gallium iodates, NaGa(IO3)2F2 (1) and NaGa(IO3)4 (2), were successfully designed and synthesized based on NaGa(IO3)3F by introducing more F- anions and replacing F- anions with IO3 groups, respectively. Structurally, in compound 1, the adjacent [GaF3(IO3)3]3- polyanions are connected in an antiparallel manner, resulting in a complete cancellation of local polarity. While in compound 2, all IO3 groups in 2D [Ga(IO3)4]∞- layers are aligned, leading to large macroscopic polarization. Additionally, chemical substitution also results in a qualitative improvement in the functional properties of compound 2. It possesses strong SHG response (12 × KDP @1064 nm) and broad optical transparency, coupled with large birefringence (0.21 @1064 nm), showcasing its promise as a promising nonlinear optical (NLO) crystal. The effects of chemical substitution between F- anions and IO3- groups on the structures and properties are discussed in detail.

LiGa(IO3 )4 : An Excellent NLO Material with Unprecedented 2D [Ga(IO3 )4 ]∞ - Layer Synthesized by Aliovalent Substitution

Nonlinear optical (NLO) crystals are indispensable for the solid-state lasers for their ability to expand wavelength spectral to the regions where the directing lasing is difficult or even impossible, yet the rational design of a high-performance NLO crystal remains a great challenge owing to the severe structural and properties' requirements. Herein, a new noncentrosymmetric (NCS) and polar gallium iodate, LiGa(IO3 )4 , with a novel 2D anionic layer, is successfully designed and synthesized by the aliovalent substitution strategy based on classic α-LiIO3 . The 2D [Ga(IO3 )4 ]∞ - layer in LiGa(IO3 )4 is built from the GaO6 octahedra and highly polarizable units IO3 . Compared with its parent compound, the partial replacement of A-site Li+ cation with main group Ga3+ cation facilitates LiGa(IO3 )4 to possess excellent NLO properties, including the large second-harmonic generation (SHG) response (14 × KH2 PO4 (KDP) @ 1064 nm), wide bandgap (4.25 eV), large birefringence (0.23 @ 1064 nm), and wide optical transparency from UV to mid-IR. These reveal that LiGa(IO3 )4 will be a promising NLO crystal.

Efficient Synthesis, Spectroscopic Characterization, and Nonlinear Optical Properties of Novel Salicylaldehyde-Based Thiosemicarbazones: Experimental and Theoretical Studies

Currently, we reported the synthesis of six novel salicylaldehyde-based thiosemicarbazones (BHCT1-HBCT6) via condensation of salicylaldehyde with respective thiosemicarbazide. Through various spectroscopic methods, UV-visible and NMR, the chemical structures of BHCT1-HBCT6 compounds were determined. Along with synthesis, a computational study was also performed at the M06/6-31G(d,p) functional. Various analyses such as natural bond orbital (NBO) analysis, natural population analysis, frontier molecular orbital (FMO) analysis, and molecular electrostatic potential surfaces were carried out to understand the nonlinear optical (NLO) characteristics of the synthesized compounds. Additionally, a comparative study was carried out between DFT and experimental results (UV-vis study), and a good agreement was observed in the results. The energy gap calculated through FMOs was found to be in decreasing order as 4.505 (FHCT2) > 4.499 (HBCT6) > 4.497 (BHCT1) = 4.497(HMCT5) > 4.386 (CHCT3) > 4.241(AHCT4) in eV. The global reactivity parameters (GRPs) were attained through E _HOMO and E _LUMO, which described the stability and hardness of novel compounds. The NBO approach confirmed the charge delocalization and stability of the molecules. Among all the investigated compounds, a larger value (557.085 a.u.) of first hyperpolarizability (β_tot) was possessed by CHCT3. The NLO response (β_tot) of BHCT1-HBCT6 was found to be 9.145, 9.33, 13.33, 5.43, 5.68, and 10.13 a.u. times larger than that of the standard para-nitroaniline molecule. These findings ascertained the potential of entitled ligands as best NLO materials for a variety of applications in modern technology.

Noncentrosymmetric γ-Cs2I4O11 Obtained from IO4 Polyhedral Rearrangements in the Centrosymmetric β-Phase

We report the synthesis and optical properties of noncentrosymmetric (NCS) γ-Cs₂I₄O₁₁ that was obtained through IO₄ polyhedral rearrangements from centrosymmetric (CS) β-Cs₂I₄O₁₁. Trifluoroacetic acid (TFA) acts as a structure-directing agent and plays a key role in the synthesis. It is suggested that the function of TFA is to promote rearrangement reactions found in the organic synthesis of stereoisomers. γ-Cs₂I₄O₁₁ crystallizes in the NCS monoclinic space group P2₁ (No. 4) and exhibits a strong second-harmonic-generation (SHG) response of 5.0 × KDP (KH₂PO₄) under 1064 nm laser radiation. Additional SHG experiments indicate that the material is type I phase matchable. First-principles calculations show that SHG intensity mainly comes from its d₃₄, d₂₁, and d₂₃ SHG tensor components. The synthetic strategy of discovering γ-Cs₂I₄O₁₁ provides a new way for designing novel NCS SHG materials.

K3V2O3F4(IO3)3: a high-performance SHG crystal containing both five and six-coordinated V5+ cations

The combination of d⁰ transition metal oxofluorides with iodate anions helps to synthesize polar crystals. Herein, a novel polar crystal, K₃V₂O₃F₄(IO₃)₃, which is the first metal vanadium iodate with two types of V⁵⁺-centered polyhedra (VO₄F₂ octahedron and VO₃F₂ trigonal bipyramid), has been prepared hydrothermally. It crystallizes in the polar space group of Cmc2₁ and its structure displays an unprecedented 0D [V₂O₃F₄(IO₃)₃]^3- anion, which is composed of Λ-shaped cis-[VO₂F₂(IO₃)₂]^3- and [VO₂F₂(IO₃)]^2- anions interconnected via the corner-sharing of one oxo anion. The synergy gained from the VO₄F₂, VO₃F₂ and IO₃ groups resulted in K₃V₂O₃F₄(IO₃)₃ exhibiting both a strong second-harmonic generation (SHG) response (1.3 × KTiOPO₄) under 2050 nm laser irradiation and a large birefringence (0.158 @ 2050 nm). This study provides a facile route for designing SHG materials by assembling various vanadium oxide-fluoride motifs and iodate anions into one compound.

BaI3O9H: a new alkaline-earth metal hydroxy iodate with two groups

A new alkali metal hydroxyl iodate BaI3O9H with a three-dimensional network structure and a moderate birefringence of 0.073 at 1064 nm.

K6(IO6H4)(HI2O6)(HIO3)2(IO3)4·2H2O: A Case of Iodate with Coexisting [I5+O3] and [I7+O6] Units

A new alkali-metal iodate, K₆(IO₆H₄)(HI₂O₆)(HIO₃)₂(IO₃)₄·2H₂O (KIOH), was successfully grown at room temperature by a slow evaporation method. To our knowledge, the title compound is the first alkali-metal iodate containing isolated [I⁵⁺O₃] and [I⁷⁺O₆] units in one structure. Both the bond valence sum and X-ray photoelectron spectroscopy confirmed this phenomenon, which is consistent with the single-crystal data. Also, the theoretical calculation results showed that the title compound is a potential birefringent material. What is more, the low-cost growth of centimeter-sized crystals for the title compound greatly enriches the structural chemistry of the iodate system.

Synthesis and Characterization of Novel Nanoparticles of Lithium Aluminum Iodate LiAl(IO3)4, and DFT Calculations of the Crystal Structure and Physical Properties

Here we report on the non-hydrothermal aqueous synthesis and characterization of nanocrystalline lithium aluminum iodate, LiAl(IO₃)₄. Morphological and compositional analyses were carried out by using scanning electron microscopy (SEM) and energy-dispersive X-ray measurements (EDX). The optical and vibrational properties of LiAl(IO₃)₄ have been studied by UV-Vis and IR spectroscopy. LiAl(IO₃)₄ is found to crystallize in the non-centrosymmetric, monoclinic P2₁ space group, contrary to what was reported previously. Theoretical simulations and Rietveld refinements of crystal structure support this finding, together with the relatively high Second Harmonic Generation (SGH) response that was observed. Electronic band structure calculations show that LiAl(IO₃)₄ crystal has an indirect band gap Egap=3.68 eV, in agreement with the experimental optical band gap Egap=3.433 eV. The complex relative permittivity and the refraction index of LiAl(IO₃)₄ have also been calculated as a function of energy, as well as its elastic constants and mechanical parameters. LiAl(IO₃)₄ is found to be a very compressible and ductile material. Our findings imply that LiAl(IO₃)₄ is a promising material for optoelectronic and non -linear optical applications.

Syntheses, Structures and Properties of Alkali and Alkaline Earth Metal Diamond-Like Compounds Li2MgMSe4 (M = Ge, Sn)

Two new diamond-like (DL) chalcogenides, Li2MgGeSe4 and Li2MgSnSe4, have been successfully synthesized using a conventional high-temperature solid-state method. The two compounds crystallize in the non-centrosymmetric space group Pmn21 with a = 8.402 (14) Å, b = 7.181 (12) Å, c = 6.728 (11) Å, Z = 2 for Li2MgSnSe4, and a = 8.2961 (7) Å, b = 7.0069 (5) Å, c = 6.6116 (6) Å, Z = 2 for Li2MgGeSe4. The calculated results show that the second harmonic generation (SHG) coefficients of Li2MgSnSe4 (d33 = 12.19 pm/v) and Li2MgGeSe4 (d33 = -14.77 pm/v), mainly deriving from the [MSe4] (M = Ge, Sn) tetrahedral units, are close to the one in the benchmark AgGaS2 (d14 = 13.7 pm/V). The calculated band gaps for Li2MgSnSe4 and Li2MgGeSe4 are 2.42 and 2.44 eV, respectively. Moreover, the two compounds are the first series of alkali and alkaline-earth metal DL compounds in the I2-II-IV-VI4 family, enriching the structural diversity of DL compounds.

Cobalt-Enhanced Mass Transfer and Catalytic Production of Sulfate Radicals in MOF-Derived CeO2 • Co3 O4 Nanoflowers for Efficient Degradation of Antibiotics

Antibiotics discharge has been a critical issue as the abuse in clinical disease treatment and aquaculture industry. Advanced oxidation process (AOPs) is regarded as a promising approach to degrade organic pollutants from wastewater, however, the catalysts for AOPs always present low activities, and uncontrollable porosities, thus hindering their further wider applications. In this work, an aliovalent-substitution strategy is employed in metal-organic framework (MOF) precursors assembly, aiming to introduce Co(II/III) into Ce-O clusters which could modify the structure of the clusters, then change the crystallization, enlarge the surface area, and regulate the morphology. The introduction of Co(II/III) also enlarges the pore size for mass transfer and enriches the active sites for the production of sulfate radicals (SO₄^• - ) in MOF-derived catalysts, leading to excellent performance in antibiotics removal. Significantly, the CeO₂ •Co₃ O₄ nanoflowers could efficiently enhance the generation of sulfate radical SO₄^• - and promote the norfloxacin removal efficiency to 99% within 20 min. The CeO₂ •Co₃ O₄ nanoflowers also present remarkable universality toward various antibiotics and organic pollutants. The aliovalent-substitution strategy is anticipated to find wide use in the exploration of high-performance MOF-derived catalysts for various applications.

High-Performance Second-Harmonic-Generation (SHG) Materials: New Developments and New Strategies

ConspectusSecond-harmonic-generation (SHG) causes the frequency doubling of light, which is very useful for generating high-energy lasers with specific wavelengths. Noncentrosymmetry (NCS) is the first requirement for an SHG process because the SHG coefficient is zero (χ² = 0) in all centrosymmetric structures. At this stage, developing novel NCS crystals is a crucial scientific topic. Assembling polar units in an addictive fashion can facilely form NCS crystals with outstanding SHG performance. In this way, our group has obtained many different NCS crystals with extremely large SHG intensities (>5 × KDP or 1 × KTP). In this Account, we first provide a brief review of the development of SHG materials and concisely highlight the features of the excellent SHG materials. Then, we present four facile and rational molecular design strategies: (1) Traditional BO₃^3--based crystals feature short absorption edges but usually suffer from relatively weak SHG performance (<5 × KDP). The combination of two types of pure π-conjugated anions (BO₃^3- and NO₃^-) in a parallel fashion in the same compound has afforded a metal borate nitrate with a strong SHG effect. (2) To overcome the problems of the weak SHG effect and small birefringence in the less anisotropic QO₄-based compounds, highly polarizable cations such as Hg²⁺ and Bi³⁺ are introduced into these systems, which greatly enhances both SHG effects and birefringence. (3) Iodate anions can be condensed into polynuclear iodate anions with a higher density of I⁵⁺ per unit cell, hence polyiodate anions can serve as excellent SHG-active groups. We developed a novel synthesis method for hydrothermal reactions under a phosphoric acid medium and obtained a series of metal polyiodates with strong SHG effects. In addition, as the number of iodate groups increases, the structural configuration of the polyiodate anion changes from linear to bent. (4) We introduce the concept of aliovalent substitution which features site-to-site atomic displacement at the structural level. Such aliovalent substitution led to new materials that have the same chemical stoichiometries or structural features as their parent compounds. Thus, aliovalent substitution can provide more experimental opportunities and afford new high-performance SHG materials. The introduction of a fluoride anion and the replacement of metal cations in the MO₆ octahedron can result in new metal iodates with balanced properties including a large SHG effect, a wide band gap, and a high laser-induced damage threshold (LIDT) value. Finally, we briefly discuss several problems associated with the studies of SHG materials and give some prospects for SHG materials in the future.

Cd3(IO3)(IO4)F2·0.1CdO: A Nonlinear-Optical Crystal with the Introduction of Fluoride into Iodate Containing Both [IO3]- and [IO4]3- Groups

A new d¹⁰ transition-metal iodate fluoride, namely, Cd₃(IO₃)(IO₄)F₂·0.1CdO, was successfully designed and synthesized via the mid-infrared hydrothermal method. It crystallizes in the polar space group R3m and features the coexistence of the [IO₃]^- and [IO₄]^3- groups. Cd₃(IO₃)(IO₄)F₂·0.1CdO has a strong second-harmonic-generation response of about 3.0 times that of KDP(KH2PO4), large birefringence (0.133 at 546.1 nm), and a wide energy band gap (4.00 eV). In addition, the power laser damage threshold (LDT) measurement indicated that it possesses a high LDT of 84.29 MW/cm², which is about 30 times that of AgGaS₂. These superior properties showed that Cd₃(IO₃)(IO₄)F₂·0.1CdO may be an excellent nonlinear-optical crystal for visible and mid-infrared application.

Na3Bi(IO3)6: An Alkali-Metal Bismuth Iodate with Intriguing One-Dimensional [BiI6O18] Chains and Pressure-Induced Structural Transition

An alkali-metal bismuth iodate, Na₃Bi(IO₃)₆, was successfully obtained by the hydrothermal method for the first time and contains intriguing one-dimensional [BiI₆O₁₈] chains. High-pressure Raman spectra were carried out to investigate the structural transition of Na₃Bi(IO₃)₆. Electronic states and anisotropic optical responses were also investigated by theoretical calculations.

Barium fluoroiodate crystals with a large band gap and birefringence

BaI₂O₅F₂ and BaIO₂F₃ have large birefringence of 0.174 and 0.133 at 1064 nm, respectively, which is owing to the rare [IO₃F]²⁻ units with high anisotropic polarizability in BaI₂O₅F₂ and the orderly arranged [IO₂F₂]⁻ units in BaIO₂F₃.

Pressure-dependent modifications in the optical and electronic properties of Fe(IO3)3: the role of Fe 3d and I 5p lone–pair electrons

The electronic and transport properties of Fe(IO3)3 have been characterized under compression. A nice correlation of bandgaps of iodates to orbital configuration is proposed giving an explanation for the 2.1 eV bandgap of Fe(IO3)3.

From Ag2 Zr(IO3 )6 to LaZr(IO3 )5 F2 : A Case of Constructing Wide-band-gap Birefringent Materials through Chemical Cosubstitution

Two mixed-metal zirconium iodates were prepared and studied as a case of chemical cosubstitution. The structure of Ag₂ Zr(IO₃ )₆ (P2₁ /c) features 0D [Zr(IO₃ )₆ ]^2- anion group and 1D [Ag(IO₃ )₂ ]^- anionic chain, with the [Zr(IO₃ )₆ ]^2- anion groups interconnected by Ag⁺ ions into 3D network; LaZr(IO₃ )₅ F₂ (P2₁ /n) features 0D [Zr(IO₃ )₅ F₂ ]^3- anion group and 2D [La(IO₃ )₅ ]^2- anionic layer, with the [Zr(IO₃ )₅ F₂ ]^3- groups interlinked by La³⁺ ions into 3D structure. Notably, LaZr(IO₃ )₅ F₂ is the first zirconium iodate fluoride reported. Wide optical band gaps of 3.77 and 4.13 eV are given for Ag₂ Zr(IO₃ )₆ and LaZr(IO₃ )₅ F₂ , respectively. Theoretical calculations confirmed that the weak d-d transition of Zr⁴⁺ in the band structure leads to a moderate band gap of Ag₂ Zr(IO₃ )₆ , and the introduction of F^- into the zirconium iodate compound results in a large band gap of LaZr(IO₃ )₅ F₂ . Both of the compounds are birefringent materials with birefringences of 0.064 @1064 nm and 0.082 @1064 nm, respectively.

Ba(IO3)F: An Alkaline-Earth-Metal Iodate Fluoride Crystal with Large Band Gap and Birefringence

An alkaline-earth-metal iodate fluoride, Ba(IO₃)F (1), was discovered by introducing F atoms into alkaline-earth-metal iodates via a hydrothermal method. The pseudo-two-dimensional (2D) [BaF]⁺ layers and [IO₃]^- anionic groups built the crystal structure, which obviously exhibited large anisotropies. The birefringence of 1 was initially tested to be 0.1256 at 589.3 nm. Besides, compared with most reported metal iodate crystals, 1 possesses a large band gap (E_g = 4.32 eV). Theoretical calculations proved that the excellent optical characteristics can be attributed to [IO₃]^- anionic groups and [BaO₄F₄]^10- polyhedra.

A study of composition effects on the bandgaps in a series of new alkali metal aluminum/gallium iodates

Four new alkali metal aluminum/gallium iodates, namely A₂M(IO₃)₄(H_0.5IO₃)₂ (A = K, Rb and M = Al, Ga), have been successfully synthesized via a hydrothermal reaction and structurally characterized through single-crystal X-ray diffraction analysis. These compounds are isostructural and crystallize in the P1[combining macron] space group (no. 2) with one formula unit in each unit cell. The rare half-protonated H_0.5IO₃ building units were identified, and their structure feature isolated [M(IO₃)₄(H_0.5IO₃)₂]^2- anions, which are separated by alkali metal cations. The optical diffuse reflectance spectroscopy measurements associated with the Tauc analysis showed direct energy gaps, which are in good agreement with the theoretical calculation prediction. Moreover, this study also indicates that the electronic properties of these compounds are mainly determined by the IO₃ and H_0.5IO₃ anionic units, and the alkali metal cations show a remarkable effect on their energy gap values, whereas the impacts of the group 13 elements aluminum and gallium are insignificant.

Coordinated regulation on critical physiochemical performances activated from mixed tetrahedral anionic ligands in new series of Sr6A4M4S16 (A = Ag, Cu; M = Ge, Sn) nonlinear optical materials

Coordinated regulation on physiochemical performances activated from mixed anionic ligands in a new series of IR NLO materials was systematically investigated.