"Ion-imprinting" strategy towards metal sulfide scavenger enables the highly selective capture of radiocesium.

Highly selective capture of radiocesium is an urgent need for environmental radioactive contamination remediation and spent fuel disposal. Herein, a strategy is proposed for construction of "inorganic ion-imprinted adsorbents" with ion recognition-separation capabilities, and a metal sulfide Cs2.33Ga2.33Sn1.67S8·H2O (FJSM-CGTS) with "imprinting effect" on Cs+ is prepared. We show that the K+ activation product of FJSM-CGTS, Cs0.51K1.82Ga2.33Sn1.67S8·H2O (FJMS-KCGTS), can reach adsorption equilibrium for Cs+ within 5 min, with a maximum adsorption capacity of 246.65 mg·g-1. FJMS-KCGTS overcomes the hindrance of Cs+ adsorption by competing ions and realizes highly selective capture of Cs+ in complex environments. It shows successful cleanup for actual 137Cs-liquid-wastes generated during industrial production with removal rates of over 99%. Ion-exchange column filled with FJMS-KCGTS can efficiently treat 540 mL Cs+-containing solutions (31.995 mg·L-1) and generates only 0.12 mL of solid waste, which enables waste solution volume reduction. Single-crystal structural analysis and density functional theory calculations are used to visualize the "ion-imprinting" process and confirm that the "imprinting effect" originates from the spatially confined effect of the framework. This work clearly reveals radiocesium capture mechanism and structure-function relationships that could inspire the development of efficient inorganic adsorbents for selective recognition and separation of key radionuclides.

(C6H15N3)1.3(NH4)1.5H1.5In3SnS8: a layered metal sulfide based on supertetrahedral T2 clusters with photoelectric response and ion exchange properties.

A new layered metal sulfide, namely (C6H15N3)1.3(NH4)1.5H1.5In3SnS8 (1, C6H15N3 = N-(2-aminoethyl) piperazine), has been solvothermally synthesized and characterized. Compound 1 crystallizes in the monoclinic space group C2/c. Its structure features a two-dimensional layer of {In3SnS8}n3n- with the (4,4) topology net, which is formed by interlinking supertetrahedral T2 clusters as secondary building units. Band structure calculations revealed that 1 had a band gap of 2.7 eV. The photoelectric response of 1 showed steady and reversible on/off cycles with an "on" state of 121.13 nA cm-2. Moreover, the activation of 1 by replacing the sluggish organic cations with harder K+ ions endowed the material with improved adsorption performances for Sr2+ ions from aqueous solutions.

New group IIIA metal phosphate-oxalates containing dimethylammonium cations with proton conductivity.

Three new group IIIA metal phosphate-oxalate (MPO) compounds, namely [(CH3)2NH2]2[M2(HPO4)2(H2PO4)2(C2O4)] (M = Al (1), Ga (2)) and [(CH3)2NH2]2[In2(HPO4)2(H2PO4)2(C2O4)]·H2O (3), have been synthesized. Their crystal structures feature an anionic layer with the sql topology net. In particular, 1 displays a proton conductivity (σ) of 9.09 × 10-3 S cm-1 at 85 °C and under 98% relative humidity, which is the highest among MPOs. This study not only endows the main group metal-based MPO family with new members, but also contributes to further understanding of the structure-directing roles of amines and provides a feasible idea for improving the proton conductivity of MPOs.

Efficient Co-Adsorption and Highly Selective Separation of Cs+ and Sr2+ with a K+ -Activated Niobium Germanate by the pH Control.

137 Cs and 90 Sr are hazardous to ecological environment and human health due to their strong radioactivity, long half-life, and high mobility. However, effective adsorption and separation of Cs+ and Sr2+ from acidic radioactive wastewater is challenging due to stability issues of material and the strong competition of protons. Herein, a K+ -activated niobium germanate (K-NGH-1) presents efficient Cs+ /Sr2+ coadsorption and highly selective Cs+ /Sr2+ separation, respectively, under different acidity conditions. In neutral solution, K-NGH-1 exhibits ultrafast adsorption kinetics and high adsorption capacity for both Cs+ and Sr2+ (qm Cs  = 182.91 mg g-1 ; qm Sr  = 41.62 mg g-1 ). In 1 M HNO3 solution, K-NGH-1 still possesses qm Cs of 91.40 mg g-1 for Cs+ but almost no adsorption for Sr2+ . Moreover, K-NGH-1 can effectively separate Cs+ from 1 M HNO3 solutions with excess competing Sr2+ and Mn + (Mn +  = Na+ , Ca2+ , Mg2+ ) ions. Thus, efficient separation of Cs+ and Sr2+ is realized under acidic conditions. Besides, K-NGH-1 shows excellent acid and radiation resistance and recyclability. All the merits above endow K-NGH-1 with the first example of niobium germanates for radionuclides remediation. This work highlights the facile pH control approach towards bifunctional ion exchangers for efficient Cs+ /Sr2+ coadsorption and selective separation.

Hybrid Germanium Bromide Perovskites with Tunable Second Harmonic Generation.

Ge-based hybrid perovskite materials have demonstrated great potential for second harmonic generation (SHG) due to the geometry and lone-pair induced non-centrosymmetric structures. Here, we report a new family of hybrid 3D Ge-based bromide perovskites AGeBr3 , A=CH3 NH3 (MA), CH(NH2 )2 (FA), Cs and FAGe0.5 Sn0.5 Br3 , crystallizing in polar space groups. These compounds exhibit tunable SHG responses, where MAGeBr3 shows the strongest SHG intensity (5×potassium dihydrogen phosphate, KDP). Structural and theoretical analysis indicate the high SHG efficiency is attributed to the displacement of Ge2+ along [111] direction and the relatively strong interactions between lone pair electrons of Ge2+ and polar MA cations along the c-axis. This work provides new structural insights for designing and fine-tuning the SHG properties in hybrid metal halide materials.

High-capacity recovery of Cs+ ions by facilely synthesized layered vanadyl oxalatophosphates with the clear insight into remediation mechanism.

Radiocesium remediation is of great significance for the sustainable development of nuclear energy and ecological protection. It is very challenging for the effective recovery of 137Cs from aqueous solutions due to its strong radioactivity, solubility and mobility. Herein, the efficient recovery of Cs+ ions has been achieved by three layered vanadyl oxalatophosphates, namely (NH4)2[(VO)2(HPO4)2C2O4]·5 H2O (NVPC), Na2[(VO)2(HPO4)2C2O4]·2 H2O (SVPC), and K2.5[(VO)2(HPO4)1.5(PO4)0.5(C2O4)]·4.5 H2O (KVPC). NVPC exhibits the ultra-fast kinetics (within 5 min) and high adsorption capacity for Cs+ (qmCs = 471.58 mg/g). It also holds broad pH durability and excellent radiation stability. Impressively, the entry of Cs+ can be directly visualized by the single-crystal structural analysis, and thus the underlying mechanism of Cs+ capture by NVPC from aqueous solutions has been illuminated at the molecular level. This is a pioneering work in the removal of radioactive ions by metal oxalatophosphate materials which highlights the great potential of metal oxalatophosphates for radionuclide remediation.

Highly Efficient Uptake of Cs+ by Robust Layered Metal-Organic Frameworks with a Distinctive Ion Exchange Mechanism.

137Cs with strong radioactivity and a long half-life is highly hazardous to human health and the environment. The efficient removal of 137Cs from complex solutions is still challenging because of its high solubility and easy mobility and the influence of interfering ions. It is highly desirable to develop effective scavengers for radiocesium remediation. Here, the highly efficient uptake of Cs+ has been realized by two robust layered metal-organic frameworks (MOFs), namely [(CH3)2NH2]In(L)2·DMF·H2O (DMF = N,N'-dimethylformamide, H2L= H2aip (5-aminoisophthalic acid) for 1 and H2hip (5-hydroxyisophthalic acid) for 2). Remarkably, 1 and 2 hold excellent acid and alkali resistance and radiation stabilities. They exhibit fast kinetics, high capacities (q m Cs = 270.86 and 297.67 mg/g for 1 and 2, respectively), excellent selectivity for Cs+ uptake, and facile elution for the regeneration of materials. Particularly, 1 and 2 can achieve efficient Cs+/Sr2+ separation in a wide range of Sr/Cs molar ratios. For example, the separation factor (SF Cs/Sr) is up to ∼320 for 1. Moreover, the Cs+ uptake and elution mechanisms have been directly elucidated at the molecular level by an unprecedented single-crystal to single-crystal (SC-SC) structural transformation, which is attributed to the strong interactions between COO- functional groups and Cs+ ions, easily exchangeable [(CH3)2NH2]+, and flexible and robust anionic layer frameworks with open windows as "pockets". This work highlights layered MOFs for the highly efficient uptake of Cs+ ions in the field of radionuclide remediation.

Highly selective cesium(I) capture under acidic conditions by a layered sulfide.

Radiocesium remediation is desirable for ecological protection, human health and sustainable development of nuclear energy. Effective capture of Cs+ from acidic solutions is still challenging, mainly due to the low stability of the adsorbing materials and the competitive adsorption of protons. Herein, the rapid and highly selective capture of Cs+ from strongly acidic solutions is achieved by a robust K+-directed layered metal sulfide KInSnS4 (InSnS-1) that exhibits excellent acid and radiation resistance. InSnS-1 possesses high adsorption capacity for Cs+ and can serve as the stationary phase in ion exchange columns to effectively remove Cs+ from neutral and acidic solutions. The adsorption of Cs+ and H3O+ is monitored by single-crystal structure analysis, and thus the underlying mechanism of selective Cs+ capture from acidic solutions is elucidated at the molecular level.

Comparing the reliability of relative bird abundance indices from standardized surveys and community science data at finer resolutions.

Biodiversity loss is a global ecological crisis that is both a driver of and response to environmental change. Understanding the connections between species declines and other components of human-natural systems extends across the physical, life, and social sciences. From an analysis perspective, this requires integration of data from different scientific domains, which often have heterogeneous scales and resolutions. Community science projects such as eBird may help to fill spatiotemporal gaps and enhance the resolution of standardized biological surveys. Comparisons between eBird and the more comprehensive North American Breeding Bird Survey (BBS) have found these datasets can produce consistent multi-year abundance trends for bird populations at national and regional scales. Here we investigate the reliability of these datasets for estimating patterns at finer resolutions, inter-annual changes in abundance within town boundaries. Using a case study of 14 focal species within Massachusetts, we calculated four indices of annual relative abundance using eBird and BBS datasets, including two different modeling approaches within each dataset. We compared the correspondence between these indices in terms of multi-year trends, annual estimates, and inter-annual changes in estimates at the state and town-level. We found correspondence between eBird and BBS multi-year trends, but this was not consistent across all species and diminished at finer, inter-annual temporal resolutions. We further show that standardizing modeling approaches can increase index reliability even between datasets at coarser temporal resolutions. Our results indicate that multiple datasets and modeling methods should be considered when estimating species population dynamics at finer temporal resolutions, but standardizing modeling approaches may improve estimate correspondence between abundance datasets. In addition, reliability of these indices at finer spatial scales may depend on habitat composition, which can impact survey accuracy.

Critical Risk Indicators (CRIs) for the electric power grid: a survey and discussion of interconnected effects.

The electric power grid is a critical societal resource connecting multiple infrastructural domains such as agriculture, transportation, and manufacturing. The electrical grid as an infrastructure is shaped by human activity and public policy in terms of demand and supply requirements. Further, the grid is subject to changes and stresses due to diverse factors including solar weather, climate, hydrology, and ecology. The emerging interconnected and complex network dependencies make such interactions increasingly dynamic, posing novel risks, and presenting new challenges to manage the coupled human-natural system. This paper provides a survey of models and methods that seek to explore the significant interconnected impact of the electric power grid and interdependent domains. We also provide relevant critical risk indicators (CRIs) across diverse domains that may be used to assess risks to electric grid reliability, including climate, ecology, hydrology, finance, space weather, and agriculture. We discuss the convergence of indicators from individual domains to explore possible systemic risk, i.e., holistic risk arising from cross-domain interconnections. Further, we propose a compositional approach to risk assessment that incorporates diverse domain expertise and information, data science, and computer science to identify domain-specific CRIs and their union in systemic risk indicators. Our study provides an important first step towards data-driven analysis and predictive modeling of risks in interconnected human-natural systems.

Layered Thiostannates with Distinct Arrangements of Mixed Cations for the Selective Capture of Cs+, Sr2+, and Eu3+ Ions.

The selective capture of radioactive cesium, strontium, and lanthanides from liquid nuclear waste is of great significance to environmental remediation and human health. Herein, the rapid and selective removal of Cs+, Sr2+, and Eu3+ ions is achieved by two metal sulfides (FJSM-SnS-2 and FJSM-SnS-3). Both structures feature [Sn3S7]n2n- layers with the mixed cations of [CH3NH3]+ and [Bmmim]+ (1-butyl-2,3-dimethylimidazolium) as templates. However, the ratios and arrangements of mixed cations in the interlayered spaces are distinct. It is unprecedented that [CH3NH3]+ and [Bmmim]+ in FJSM-SnS-2 are alternatingly arranged in different interlayered spaces, whereas they in FJSM-SnS-3 are located in the same interlayered spaces. It is the first time that the ionic liquid cation and protonated organic amine have been simultaneously incorporated into metal sulfides. Both compounds show high capacities, rapid kinetics, and a wide pH active range for Cs+, Sr2+, and Eu3+. Even under excess Na+ ions, both show excellent selectivity in capturing trace Sr2+ and Eu3+ ions. FJSM-SnS-3 presents the highest KdEu to date. They still retain high removal efficiency even after intense ß and γ radiation. Moreover, it is first confirmed by the in situ tracking method of mass spectrometry that the large-sized [Bmmim]+ ions are exchangeable. It is found that the arrangement of cations between interlayered spaces is a crucial factor affecting ion exchange performance. This work will likely change the consensus that large-sized organic cations are difficult to be exchanged and thus further highlight the great potential of metal sulfide ion exchangers for radionuclide remediation.

Robust and Flexible Thioantimonate Materials for Cs+ Remediation with Distinctive Structural Transformation: A Clear Insight into the Ion-Exchange Mechanism.

It is imperative yet challenging to efficiently sequester the 137Cs+ ion from aqueous solutions because of its highly environmental mobility and extremely high radiotoxicity. The systematical clarification for underlying mechanism of Cs+ removal and elution at the molecular level is rare. Here, efficient Cs+ capture is achieved by a thioantimonate [MeNH3]3Sb9S15 (FJSM-SbS) with high capacity, fast kinetics, wide pH durability, excellent ß and γ radiation resistances, and facile elution. The Cs+ removal is not significantly impacted by coexisting Na+, K+, Ca2+, Mg2+, and Sr2+ ions which is beneficial to the remediation of Cs+-contaminated real waters. Importantly, the mechanism is directly illuminated by revealing an unprecedented single-crystal to single-crystal structural transformation upon Cs+ uptake and elution processes. The superior Cs+ removal results from an unusual synergy from strong affinity of soft S2- with Cs+, easily exchangeable [MeNH3]+ cations, and the flexible and robust framework of FJSM-SbS with open windows as trappers.

The Uptake of Hazardous Metal Ions into a High-Nuclearity Cluster-Based Compound with Structural Transformation and Proton Conduction.

The discovery of novel high-nuclearity oxo-clusters considerably promotes the development of cluster science. We report a high-nuclearity oxo-cluster-based compound with acid/alkali-resistance and radiation stabilities, namely, (H3O)7[Cd7Sb24O24(l-tta)9(l-Htta)3(H2O)6]·29H2O (FJSM-CA; l-H4tta = l-tartaric acid), which features a two-dimensionally anionic layer based on the largest Sb-oxo-clusters with 28-metal-ion-core [Cd4Sb24O24]. It is challenging to efficiently capture Sr2+, Ba2+ (analogue of 226Ra), and [UO2]2+ ions from aqueous solutions due to their high water solubility and environmental mobility, while it is unprecedented that a novel Sb-oxo-cluster-based framework material FJSM-CA can efficiently remove these hazardous ions accompanied with intriguing structural transformations. Especially, it shows fast ion-exchange abilities for Sr2+, Ba2+, and [UO2]2+ (reaches equilibrium within 2, 10, and 20 min, respectively) and high exchange capacity (121.91 mg/g), removal rate R (96%), and distribution coefficient KdU (2.46 × 104 mL/g) for uranium. Moreover, the underlying mechanism is clearly revealed, which is attributed to strong electrostatic interactions between exchanged cations and highly negative-charged frameworks and the strong affinity of (COO)- groups for these cations. Proton conduction of the pristine and Sr2+, Ba2+, [UO2]2+-loaded products was investigated. This work highlights the design of new oxo-cluster-based materials for radionuclide remediation and proton conduction performance.

Unexpected Roles of Alkali-Metal Cations in the Assembly of Low-Valent Uranium Sulfate Molecular Complexes.

The directing effect of coordinating ligands in the formation of uranium molecular complexes has been well established, but the role of counterions in metal-ligand interactions remains ambiguous and requires further investigation. In this work, we describe the targeted isolation, through the choice of alkali-metal ions, of a family of tetravalent uranium sulfates, showing the influence of the overall topology and, unexpectedly, the UIV nuclearity upon the inclusion of such countercations. Analyses of the structures of uranium(IV) oxo/hydroxosulfate oligomeric species isolated from consistent synthetic conditions reveal that the incorporation of Na+ and Rb+ promotes the crystallization of 0D discrete clusters with a hexanuclear [U6O4(OH)4(H2O)4]12+ core, whereas the larger Cs+ ion allows for the isolation of a 2D-layered oligomer with a less condensed trinuclear [U3(O)]10+ center. This finding expands the prevalent view that counterions play an innocent role in molecular complex synthesis, affecting only the overall packing but not the local oligomerization. Interestingly, trends in nuclearity appear to correlate with the hydration enthalpies of alkali-metal cations, such that the alkali-metal cations with larger hydration enthalpies correspond to more hydrated complexes and cluster cores. These findings afford new insights into the mechanism of nucleation of UIV, and they also open a new path for the rational design and synthesis of targeted molecular complexes.

Fast and Selective Removal of Aqueous Uranium by a K+-Activated Robust Zeolitic Sulfide with Wide pH Resistance.

For the nuclear industry, uranium is not only an important strategic resource but also a serious global contaminant with radiotoxicity and high chemotoxicity. It is very important to efficiently capture uranium from complex aqueous solutions for further treatment and disposal of nuclear wastes. Herein, we first demonstrate the suitability of a three-dimensional (3D) water-stable K+-exchanged zeolitic sulfide, namely K@GaSnS-1, for the remediation of radioactive and toxic uranium by ion exchange. In comparison to the pristine compound GaSnS-1, the K+-activated porous sulfide K@GaSnS-1 exhibits faster [UO2]2+ ion uptake kinetics, following the pseudo-second-order adsorption model. Further studies indicate that K@GaSnS-1 shows high exchange capacity (qmU = 147.6 mg/g) and wide pH resistance (pH 2.75-10.87). In particular, it can efficiently capture [UO2]2+ ion even when excessive amounts of Na+, K+, Mg2+, and Ca2+ ions are present. The highest distribution coefficient value Kd, signifying the affinity and selectivity for [UO2]2+ ion, reaches as high as 1.24 × 104 mL/g. More importantly, the uranium in corresponding exchanged samples can be facilely and effectively eluted by a low-cost and eco-friendly method. These merits of K@GaSnS-1 make it promising for the effective and selective removal of uranium from complex contaminated water.

Fast and Effective Decontamination of Aqueous Mercury by a Highly Stable Zeolitic-like Chalcogenide.

Highly efficient and effective removal of mercury from water, especially at very low ionic concentration, remains a grand challenge for ecosystem protection and human health. Herein, we present the synthesis, crystal structure, and mercury uptake performance of a new heterometallic chalcogenidometalate, namely, [TAEAH][TAEAH2]0.6Ga2.2Sn1.8S8·H2O (GaSnS-1; TAEA = Tris(2-aminoethyl)amine). GaSnS-1 features a three-dimensional (3D) zeolite-typed (RWY) framework structure of [Ga2.2Sn1.8S8] n2.2 n- that is constructed by corner-sharing of supertetrahedral [Ga2.2Sn1.8S10]6.2- T2 clusters. The equilibrium model study indicated that the maximum Hg2+ saturation capacity of GaSnS-1 was 213.9 mg/g. GaSnS-1 possessed extremely rapid adsorption kinetics following the pseudo-second-order model with a k2 of 5.65 × 102 g·mg-1·min-1. Particularly, GaSnS-1 exhibited excellent selectivity for Hg2+ ions with a high distribution coefficient Kd value of 1.62 × 107 mL/g and high removal efficiency of close to 100%. The superior Hg2+ ion adsorption performance was also impressive despite the presence of excessive competing cations and the acidic/basic conditions. Furthermore, a simple chromatographic column loaded with GaSnS-1 microcrystals is capable of rapidly and effectively capturing Hg2+ ions far below the upper limit (2 ppb, USA-EPA) of drinking water. These advantages of GaSnS-1 make it a promising candidate for the fast and efficient remediation of Hg2+-contaminated water sources.

Efficient Removal of [UO2]2+, Cs+, and Sr2+ Ions by Radiation-Resistant Gallium Thioantimonates.

Unconventional ion exchangers can achieve efficient removal of [UO2]2+, Cs+, and Sr2+ ions from complex aqueous solutions and are of great interest for environmental remediation. We report two new gallium thioantimonates, [Me2NH2]2[Ga2Sb2S7]·H2O (FJSM-GAS-1) and [Et2NH2]2[Ga2Sb2S7]·H2O (FJSM-GAS-2), which present excellent ion exchange properties for [UO2]2+, Cs+, and Sr2+ ions. They exhibit high ion exchange capacities for [UO2]2+, Cs+, and Sr2+ ions ( qmU = 196 mg/g, qmCs = 164 mg/g, and qmSr = 80 mg/g for FJSM-GAS-1, qmU = 144 mg/g for FJSM-GAS-2) and short equilibrium times for [UO2]2+ ion exchange (5 min for FJSM-GAS-1 and 15 min for FJSM-GAS-2, respectively). Both compounds display active ion exchange with [UO2]2+ in the pH range of 2.9-10.5. Moreover, the sulfide compounds could maintain high distribution coefficients KdU even in the presence of excess Na+, Ca2+, and HCO3-. The distribution coefficient KdU of 6.06 × 106 mL/g exhibited by FJSM-GAS-1 is the highest among the reported U adsorbents. The [UO2]2+-laden products can be recycled by conveniently eluting the uranium with a low-cost method. These advantages combined with facile synthesis, as well as ß and γ radiation resistance, make FJSM-GAS-1 and FJSM-GAS-2 promising for selective separations in nuclear waste remediation.

[CH3 NH3 ]4 Ga4 SbS9 S0.28 O0.72 H: A Three-Dimensionally Open-Framework Heterometallic Chalcogenidoantimonate Exhibiting Ni2+ Ion-Exchange Property.

An open-framework chalcogenidoantimonate, namely, [CH3 NH3 ]4 Ga4 SbS9 S0.28 O0.72 H (1), has been solvothermally synthesized and structurally characterized. Interestingly, 1 showed Ni2+ ion-exchange properties and wide pH resistance, with a maximum exchange capacity of 76.9 mg g-1 . To the best of our knowledge, this is the first example of amine-directed three-dimensional (3D) heterometallic chalcogenidometalates for highly selective Ni2+ ion capture with a high distribution coefficient (Kd =1.65×105  mL g-1 ).

Layered A2Sn3S7·1.25H2O (A = Organic Cation) as Efficient Ion-Exchanger for Rare Earth Element Recovery.

Exploring new ion-exchangers for the recovery of rare earth elements (REEs) and recycling is worthwhile for the high-tech industry and an eco-friendly sustainable economy. The efficient enrichment of low concentration REE from complex aqueous solutions containing large excess of competitive ions is challenging. Here we present a chalcogenide example as a superior REE ion-exchanger efficiently removing them from very complex aqueous solutions, (Me2NH2)1.33(Me3NH)0.67 Sn3S7·1.25H2O (FJSM-SnS). The material exhibits fast and efficient ion exchange behavior with short equilibrium time (<5 min), high adsorption capacity (139 mg/g for Eu, 147 mg/g for Tb, 126 mg/g for Nd), wide pH resistance (1.9-8.5), the largest distribution coefficient (Kd) value of 6.5 × 106 mL/g, good selectivity against Al3+, Fe3+, and Na+ ions, and high recovery rate (>99%) at low concentrations. Moreover, after ion-exchange, the REE in corresponding exchanged products could be easily recovered by elution. FJSM-SnS has superior capacity and faster absorption kinetics than other states of the artificial REE sorbents such as Al2O3/EG, clay minerals, zeolite, and activated carbon.

[CH3NH3]2Ag4SnIV2SnIIS8: An Open-Framework Mixed-Valent Chalcogenidostannate.

An open-framework chalcogenidostannate, namely, [CH3NH3]2Ag4SnIV2SnIIS8 (1), has been solvothermally synthesized and structurally characterized, which represents the first organically templated three-dimensional (3D) Ag-Sn-S compound containing the mixed valence of Sn(IV)/Sn(II) and displays visible-light-driven photocatalytic activity for degradation of crystal violet (CV).