Experimental investigation of radiocesium sorption on ceramic clay using a batch method

In this study, radiocesium sorption on ceramic clay was investigated as a function of particle size and initial ¹³⁷Cs concentration using a batch method. Ceramic clay samples taken from the Sö?üt(?nisar) clay deposit were composed of kaolinite, dickite and quartz. The equilibrium time and the liquid–solid ratio were determined as 60 min and 250 mL g^?1, respectively. The distribution coefficients (K _d) for variable liquid–solid ratio and the percentage adsorption (P _Ad) were calculated. The values of K _d and P _Ad ranged from 483 to 3165 mL g^?1 and 34–93%, respectively. The K _d and P _Ad values increased with increasing particle size, but decreased with increasing initial concentration. The sorption data were interpreted in terms of a Langmuir isotherm. The results indicated that the Sö?üt(?nhisar) ceramic clay has good sorption capacity for cesium.     

Facile synthesis of 5A zeolite from attapulgite clay for adsorption of <Emphasis Type="Italic">n</Emphasis>-paraffins

5A zeolites were facilely synthesized from attapulgite clay and sodium aluminate precursors. The optimum synthesis condition for 4A zeolite (Na-form) were H₂O/attapulgite ratio of 40:1 volume/mass, NaOH/attapulgite mass ratio of 2.35:1, the crystallization time was 4 h at 80–85 °C. The 4A zeolite was converted to related 5A zeolite (Ca-form) through ionic exchanges using calcium chloride solution with the Si/Al mole ratio of 1.3. SEM images demonstrated that as-synthesized 5A zeolites are ordered cubic crystals, average crystals length dimension is 1–2 μm. And the zeolites product had a specific surface area of 482 m² g^?1 and total pore volume of 0.274 cm³ g^?1. The static adsorption experiments showed that the equilibrium adsorption capacities of n-decane and n-pentadecane on produced 5A zeolite were 0.253 and 0.510 g g^?1, respectively. And the adsorption equilibrium time of n-decane and n-pentadecane on 5A zeolite were 45 and 60 min, respectively. The experimental adsorption data of n-decane and n-pentadecane on three zeolites could be properly fitted by the Langmuir–Freundlich isotherm model.     

Effective removal of ciprofloxacin from aqueous solutions using magnetic metal–organic framework sorbents: mechanisms,isotherms and kinetics

Metal–organic framework sorbents [MIL-100(Fe), MOF-235(Fe)], Fe₃O₄ nanoparticles and metal–organic framework loaded on iron oxide nanoparticles [Fe₃O₄@MIL-100(Fe) and Fe₃O₄@MOF-235(Fe)] were prepared and examined for ciprofloxacin (CIP) removal. The results showed that sorption kinetics of CIP by Fe₃O₄@MIL-100(Fe) follows the Elovich and pseudo-second-order models indicating that the sorption is both chemisorption and physical adsorption, whereas the sorption to other sorbents occurs mainly by physical sorption. The sorption isotherm studies revealed that Langmuir model provided the best fit to all the experimental data. The thermodynamic studies showed that CIP removal is spontaneous (ΔG° = 2.28 kJ/mol) and endothermic (ΔH° = 18.39 kJ/mol). It was also found that among the sorbents investigated for CIP removal, Fe₃O₄@MIL-100(Fe) has the highest maximum monolayer adsorption capacity of 322.58 mg/g.     

Comparative efficacy of locally isolated fungal strains for Pb(II) removal and recovery from water

The present investigation aimed to study and compare the efficiency of non-viable fungal isolates to remove divalent lead (Pb(II)) from aqueous streams. The selected fungal isolates showed identity with Aspergillus caespitosus, Aureobasidium sp. RBSS-303 and Aspergillus flavus HF5 as confirmed using gene sequencing of ITS regions of the ribosomal DNA (rDNA). The obtained equilibrium data for Pb(II) biosorption of A. caespitosus fitted better to Langmuir isotherm with maximum sorption capacity of 351.0 mg/g and A. sp. RBSS-303 and A. flavus HF5 showed good fit to Freundlich isotherm with maximum sorption capacity of 271.5 and 346.3 mg/g respectively. The values of thermodynamic factors ascertained the nature of adsorption process is endothermic with A. caespitosus and A. flavus HF5 but exothermic with A. sp. RBSS-303. The experimental data for Pb(II) biosorption fits very well to pseudo second order kinetic model. With HCl the maximum 85.5, 75.3, 73.7% recovery of Pb(II) was obtained from A. caespitosus, A. sp. RBSS-303 and A. flavus HF5, respectively. The observed percentage loss in sorption capacity of Pb(II) was 3.9% by A. flavus HF5, 12.2% by A. caespitosus and 26.6% by A. sp. RBSS-303 after five cyclic studies of sorption and desorption. Results from the study confirmed the efficiency order of A. caespitosus > A. flavus HF5 > A. sp. RBSS-303 to remove and recover Pb(II) from aqueous solution. Finally, the fungal biosorbents can be used as soil conditioning agent after compositing into valuables fungal protein.     

Dye removal using 4A-zeolite/polyvinyl alcohol mixed matrix membrane adsorbents: preparation,characterization, adsorption,kinetics, and thermodynamics

In pursuit of improving performance of the methylene blue adsorption process, the potential of a novel 4A-zeolite/polyvinyl alcohol (PVA) membrane adsorbent was investigated. Adding 4A-zeolite particles to the PVA membrane adsorbent provided an effective structure for the adsorptive membrane in dye removal processes. Effect of zeolite content was also studied via synthesis of different mixed matrix membrane adsorbents (MMMAs) with 5, 10, 15, and 20 wt% 4A-zeolite content. Morphology of MMMAs was analyzed by scanning electron microscope and the intermolecular interactions were determined by Fourier transform infrared spectroscopy. X-ray diffraction was performed to determine the crystal structure of MMMAs. For the sake of finding optimum condition, the adsorption capacity was examined at various operating parameters, such as contact time, temperature, pH, and initial concentration. The maximum value of the adsorption capacity (q _e) of 41.08 mg g^?1 and the highest removal efficiency of 87.41 % were obtained by applying 20 wt% loading of 4A-zeolite. The experimental data were fitted well with the Freundlich adsorption isotherm model (R ² = 0.9917) compared with the Langmuir (R ² = 0.9489) and the Tempkin (R ² = 0.8886) adsorption isotherm models, and the adsorption kinetic data verified the best fitting with the pseudo-second-order model (R ² = 0.9999). The estimated data for Gibb’s free energy (ΔG°) showed that the adsorption process is spontaneous at lower temperature values and non-spontaneous at higher temperature values. Other evaluated thermodynamic parameters such as changing in enthalpy (ΔH°) and entropy (ΔS°) revealed that the adsorption process is exothermic with an increase in orderliness at the solid/solution interface.     

Diethylenetriamine-functionalized chitosan magnetic nano-based particles for the sorption of rare earth metal ions [Nd(III), Dy(III) and Yb(III)]

The recovery of three rare earth (RE) metals ions [Yb(III), Dy(III) and Nd(III), belonging to heavy, mild and light REs, respectively] was investigated using hybrid chitosan-magnetic nano-based particles functionalized by diethylenetriamine (DETA). The effect of pH on sorption performance was analyzed: the optimum initial pH value was found close to 5 (equilibrium pH value close to 6.5). The nanometric size of sorbent particles (30–50 nm) minimized the contribution of resistance to intraparticle diffusion on the control of uptake kinetics, which is efficiently modeled using the pseudo-second order rate equation: under selected experimental conditions the contact time required for reaching equilibrium was less than 1 h. Sorption isotherms were efficiently modeled using the Langmuir equation: maximum sorption capacities reached about 50 mg metal g^?1, regardless of the RE. The temperature had a very limited effect on sorption capacity (in the range 300–320 K). The thermodynamic parameters were determined: the sorption was endothermic (positive values of ΔH°), spontaneous (negative values of ΔG°) and contributed to increasing the disorder of the system (positive values of ΔS°). The three REs have similar sorption properties on DETA-functionalized chitosan magnetic nano-based particles: the selective separation of these elements seems to be difficult. The sorbed metal ions can be removed from loaded sorbents using thiourea, and the sorbent can be recycled for at least five sorption/desorption cycles with a limited loss in sorption performance (by less than 6 %). The saturation magnetization was close to 20 emu g^?1; this means that nano-based superparamagnetic particles can be readily recovered by an external magnetic field, making the processing of these materials easy.     

Oxygen isotope exchange in praseodymium nickelate

Oxygen surface exchange kinetics and diffusion were studied in Pr₂NiO_4?+?δ (PNO) by the isotope exchange method with gas phase equilibration in the temperature range of 600–800 °C and oxygen pressure range of 0.33–1.62 kPa. The oxygen heterogeneous exchange rate (r_H), oxygen diffusion coefficient (D), rates of oxygen dissociative adsorption (r_a), and oxygen incorporation (r_i) were calculated along with the apparent activation energies of oxygen surface exchange and diffusion processes. The temperature dependence of r_H was found to benon-linear in Arrhenius coordinates. The apparent activation energy changed from 1.4?±?0.2 eV at T?>?700 °C to 2.0?±?0.1 eV. This might be attributed to the change in the rate-determining stage of oxygen exchange for Pr₂NiO_4?+?δ at T ~?700 °C, because of a shift in the ratio between r_a and r_i caused by the difference in their activation energies. Possible reasons for the observed changes in the rate-determining stage are discussed.     

Treatment of chromium effluent by adsorption on chitosan activated with ionic liquids

This study proposes, verifies, and refines the use of biopolymers treated with two new ionic liquids (ILs) (sec-butylammonium acetate and n-octylammonium acetate), as a platform for chromium adsorption. The ILs were synthesized, characterized, and applied to chitosan treatment. Analyzing the size distribution of microparticles of chitosan and chitosan activated with ILs (sec-butylammonium acetate and n-octylammonium acetate), we observed that a little decrease in the particle size occurred with the activation of chitosan (176 ± 0.02 μm to 167 ± 0.054 and 168.5 ± 0.05 μm, respectively), as well as changes in the X-ray diffraction FTIR_ATR spectra. Further studies were performed using the best adsorbent – chitosan treated with sec-butylammonium acetate. In this case, the chromium VI concentration in the sample was reduced by more than 99% when using chitosan treated with IL sec-butylammonium acetate. The best reaction time was determined as 1 h, which allowed a chromium adsorption of 99.1% and the adsorption kinetic data were best represented by the second-order model (k₂ = 11.7258 g mg^?1 min^?1). The maximum adsorption capacity was obtained using the Langmuir isotherm model (20.833 mg g^?1 at pH 4 during 1 h, using 1.0 g of chitosan), and the adsorption efficiency was enhanced at 25 °C by the Freundlich isotherm model, in which the constants KF and n were determined as 0.875 mg L^?1 and 1.610, respectively.     

Study of the gadolinium sorption on the C100 ion-exchange resin for the development of the antineutrino detector targets

Adsorption of the gadolinium from H₂O and HCl solutions on the ion-exchange resin C100 is investigated. The experiments were carried out by varying the acidity of the liquid phase, the amount of sorbent, and the temperature. The maximal sorption of the ions Gd³⁺ is observed from the solution 0–0.2 M HCl under optimal conditions, the sorption reaches more than 99.5%. Sorption of Gd³⁺ on C100 from H₂O solution occurs most intensively during the first 3 min then for 30 min the system smoothly comes to equilibrium. The maximal sorption capacity of the resin C100 amounted to 1.2 ± 0.1 mmol g^?1. The thermodynamic parameters of sorption: ΔG = ? 24.20 kJ mol^?1, ΔS = ? 90.27 J mol^?1 K^?1, ?H = ? 50.93 kJ mol^?1 were evaluated. It is shown that the sorption of gadolinium on the ion-exchange resin C100 is described by models of kinetically pseudo-first and pseudo-second order. It is established that the Gd³⁺ sorption on the C100 resin is reversible second order chemical reaction.     

Synthesis and characterization of <Emphasis Type="Italic">β</Emphasis>-cyclodextrin–carboxymethyl cellulose–graphene oxide composite materials and its application for removal of basic fuchsin

A novel β-cyclodextrin–carboxymethyl cellulose–graphene oxide composite material (β-CD–CMC–GO) was synthesized, and its application as excellent adsorbents was carried out for removal basic fuchsin (BF) in aqueous solution. The structure and morphology of β-CD–CMC–GO composite material were characterized by using FTIR, SEM, TEM, XRD, TG and DSC methods. The composites could remove basic fuchsin from aqueous solution efficiently. The adsorption experiment was carried out and the optimum experimental conditions were ascertained. The highest adsorption efficiency was obtained 97.3% at 0.015 g/mL dosage of β-CD–CMC–GO, the temperature of 25 °C and time of 2.5 h. Adsorption kinetics, adsorption isotherm and adsorption thermodynamic were used to analyze the adsorption system. The experimental data of adsorption kinetics of system were well followed by pseudo-second-order equation. The adsorption isotherm data were fitted using Langmuir isotherm model and Freundlich isotherm model. The maximum adsorption capacity of basic fuchsin reached 58.65 mg/g. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. The adsorbent has excellent regeneration ability and reproducibility. The proposed method shows that the β-CD–CMC–GO could be applied to removal of basic fuchsin in wastewater with satisfactory result.     

Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction,rotational constants,and theoretical calculations

The molecular structure and conformation of nitrobenzene has been reinvestigated by gas-phase electron diffraction (GED), combined analysis of GED and microwave (MW) spectroscopic data, and quantum chemical calculations. The equilibrium r _e structure of nitrobenzene was determined by a joint analysis of the GED data and rotational constants taken from the literature. The necessary anharmonic vibrational corrections to the internuclear distances (r _e ? r _a) and to rotational constants (B _e ⁽ⁱ⁾  ? B ₀ ⁽ⁱ⁾ ) were calculated from the B3LYP/cc-pVTZ quadratic and cubic force fields. A combined analysis of GED and MW data led to following structural parameters (r _e) of planar nitrobenzene (the total estimated uncertainties are in parentheses): r(C–C)_av = 1.391(3) Å, r(C–N) = 1.468(4) Å, r(N–O) = 1.223(2) Å, r(C–H)_av = 1.071(3) Å, \({\angle}\)C2–C1–C6 = 123.5(6)°, \({\angle}\)C1–C2–C3 = 117.8(3)°, \({\angle}\)C2–C3–C4 = 120.3(3)°, \({\angle}\)C3–C4–C5 = 120.5(6)°, \({\angle}\)C–C–N = 118.2(3)°, \({\angle}\)C–N–O = 117.9(2)°, \({\angle}\)O–N–O = 124.2(4)°, \({\angle}\)(C–C–H)_av = 120.6(20)°. These structural parameters reproduce the experimental B ₀ ⁽ⁱ⁾ values within 0.05 MHz. The experimental results are in good agreement with the theoretical calculations. The barrier height to internal rotation of nitro group, 4.1±1.0 kcal/mol, was estimated from the GED analysis using a dynamic model. The equilibrium structure was also calculated using the experimental rotational constants for nitrobenzene isotopomers and theoretical rotation–vibration interaction constants.     

The Influence of Nonionic Surfactant Adsorption on Enzymatic Hydrolysis of Oil Palm Fruit Bunch

Nonionic surfactants have been utilized to improve the enzymatic hydrolysis of lignocellulosic materials. However, the role of surfactant adsorption affecting enzymatic hydrolysis has not been elaborated well. In this work, nonionic surfactants differing in their molecular structures, namely the polyoxyethylene sorbitan monooleate (Tween 80), the secondary alcohol ethoxylate (Tergitol 15-S-9), and the branched alcohol ethoxylate (Tergitol TMN-6), were studied for their effects on the enzymatic hydrolysis of palm fruit bunch (PFB). The PFB was pretreated with a 10% w/v sodium hydroxide solution and then hydrolyzed using the cellulase enzyme from Trichoderma reesei (ATCC 26921) at 50 °C and pH 5. The optimal conditions providing similar yields of reducing sugar required Tween 80 and Tergitol TMN-6 at 0.25% w/v, while Tergitol 15-S-9 was required at 0.1% w/v. All the surfactants improved the enzymatic conversion efficiency and reduced unproductive binding of the enzyme to lignin. In addition, the adsorption isotherm of cellulase was fit well by the Freundlich isotherm, while adsorption of the three nonionic surfactants agreed well with the Langmuir isotherm. Adsorption capacities of the three nonionic surfactants were consistent with their enhancement efficiencies in hydrolysis. The critical micelle concentration was observed as a key property of nonionic surfactant for adsorption capacity.     

Synthesis,crystal structure of a new tetranuclear Ni<Stack><Subscript>2</Subscript><Superscript>II</Superscript></Stack>Cu<Stack><Subscript>2</Subscript><Superscript>II</Superscript></Stack> complex containing a macrocyclic ligand

The first inorg/organic hybrid complex incorporating the macrocyclic oxamide, of formula [(NiL)₂Cu₂(μ-NSC)₂(NSC)₂] (1), (NiL, H₂L = 2, 3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien), have been synthesized and structurally characterized. The crystals crystallize in the triclinic system, space group P-1, for (1) a = 8.319(3) Å, b = 10.434(4) Å, c = 14.166(5) Å, a = 107.030(5)°, β  =  91.257(5)°, γ = 107.623(5)°. The complex involved both bridging N, S-ligand, and oxamide ligand, C–H?S interactions and NCS → Ni weak coordination interactions making the complex superamolecular.     

Synthesis,crystal structure,and thermodynamics of a high-nitrogen copper complex with <Emphasis Type="Italic">N</Emphasis>, <Emphasis Type="Italic">N</Emphasis>-bis-(1(2)H-tetrazol-5-yl) amine

A new high-nitrogen complex [Cu(Hbta)₂]·4H₂O (H₂bta = N,N-bis-(1(2)H-tetrazol-5-yl) amine) was synthesized and characterized by elemental analysis, single crystal X-ray diffraction and thermogravimetric analyses. X-ray structural analyses revealed that the crystal was monoclinic, space group P2(1)/c with lattice parameters a = 14.695(3) Å, b = 6.975(2) Å, c = 18.807(3) Å, β = 126.603(1)°, Z = 4, D _c = 1.888 g cm^?3, and F(000) = 892. The complex exhibits a 3D supermolecular structure which is built up from 1D zigzag chains. The enthalpy change of the reaction of formation for the complex was determined by an RD496–III microcalorimeter at 25 °C with the value of ?47.905 ± 0.021 kJ mol^?1. In addition, the thermodynamics of the reaction of formation of the complex was investigated and the fundamental parameters k, E, n, \( \Updelta S_{ \ne }^{{{\uptheta}}} \), \( \Updelta H_{ \ne }^{{{\uptheta}}} \), and \( \Updelta G_{ \ne }^{{{\uptheta}}} \) were obtained. The effects of the complex on the thermal decomposition behaviors of the main component of solid propellant (HMX and RDX) indicated that the complex possessed good performance for HMX and RDX.     

2-Propylamino-5-[4-(2-hydroxy-3,5-dichlorobenzylideneamino) phenyl]-1,3,4-thiadiazole: X-ray and DFT-calculated structures

2-Propylamino-5-[4-(2-hydroxy-3,5-dichlorobenzylideneamino) phenyl]-1,3,4-thiadiazole, formulated as C₁₈H₁₆Cl₂N₄OS (I), was synthesized. The crystal and molecular structure of (I) have been determined by ¹H-NMR, IR, and X-ray single crystal diffraction. The compound (I) crystallizes in the monoclinic, space group P2(1)/c with unit cell parameters a = 9.0576(2) Å, b = 24.3382(8) Å, c = 9.0585(2) Å, M _r = 407.31, V = 1851.13(9) Å³, Z = 4, R ₁ = 0.036, and wR ₂ = 0.096. Molecular geometry from X-ray experiment of (I) in the ground state has been compared using the density functional method (B3LYP) with 6-31G(d) basis set. To determine conformational flexibility, molecular energy profile of (I) was obtained by semi-empirical (PM3) calculations with respect to selected degree of torsional freedom, which was varied from ?180° to +180° in steps of 10°. The results are indicative that the Schiff base, which contains a thiadiazole ring, prefers to be in E-configuration. In addition, molecular electrostatic potential, frontier molecular orbitals, and natural bond orbitals analysis were performed by the B3LYP/6-31G(d) method.     

Solubility of B-Nb<Subscript>2</Subscript>O<Subscript>5</Subscript> and the Hydrolysis of Niobium(V) in Aqueous Solution as a Function of Temperature and Ionic Strength

B-Nb₂O₅ was recrystallized from commercially available oxide, and XRD analyses indicated that it is stable in contact with solutions over the pH range 0 to 9, whereas solid polyniobates such as Na₈Nb₆O₁₉?13H₂O(s) appear to predominate at pH>9. Solubilities of the crystalline B-Nb₂O₅ were determined in five NaClO₄ solutions (0.1≤I _m /mol?kg^?1≤1.0) over a wide pH range at (25.0±0.1)?°C and at 0.1 MPa. A limited number of measurements were also made at I _m =6.0 mol?kg^?1, whereas at I _m =1.0 mol?kg^?1 the full range of pH was also covered at (10, 50 and 70)?°C. The pH of these solutions was fixed using either HClO₄ (pH≤4) or NaOH (pH≥10) and determined by mass balance, whereas the pH on the molality scale was measured in buffer mixtures of acetic acid?+?acetate (4≤pH≤6), Bis-Tris (pH≈7), Tris (pH≈8) and boric acid?+?borate (pH≈9). Treatment of the solubility results indicated the presence of four species, \(\mathrm{Nb(OH)}_{n}^{5-n}\) (where n=4–7), so that the molal solubility quotients were determined according to:

$0\mathrm{.5Nb}_{2}\mathrm{O}_{5}\mathrm{(cr)+0}\mathrm{.5(2}n-5\mathrm{)H}_{2}\mathrm{O(l)}_{\leftarrow}^{\to}\mathrm{Nb(OH)}_{n}^{5-n}+(n-5)\mathrm{H}^{+}\quad (n=4\mbox{--}7)$

and were fitted empirically as a function of ionic strength and temperature, including the appropriate Debye-Hückel term. A Specific Interaction Theory (SIT) approach was also attempted. The former approach yielded the following values of log?₁₀ K _sn (infinite dilution) at 25?°C: ?(7.4±0.2) for n=4; ?(9.1±0.1) for n=5; ?(14.1±0.3) for n=6; and ?(23.9±0.6) for n=7. Given the experimental uncertainties (2σ), it is interesting to note that the effect of ionic strength only exceeded the combined uncertainties significantly in the case of log?₁₀ K _s6 to I _m =1.0 mol?kg^?1, such that these values may be of use by defining their magnitudes in other media. Values of Δ _f G ^o, Δ _f H ^o, S ^o and \(C_{p}^{\mathrm{o}}\) (298.15 K, 0.1 MPa) for each hydrolysis product were calculated and tabulated.

     

A procedure for studying the sorption of ethanol vapor on a monomolecular Langmuir-Blodgett arachic acid film

The paper presents the results of studies of the sorption of ethanol from the gas phase by a monomolecular arachic acid layer deposited by the Langmuir-Blodgett method onto the surface of a nickel substrate. Studies were performed using a working model based on a field-effect transistor. Sorption was accompanied by changes in the potential of the nickel substrate. The dependence of transistor current I _D on time t was related to the conditions of Langmuir-Blodgett film deposition. The value and characteristic time of signal variations as the atmosphere changed depended on the pressure of monolayer deposition and, therefore, monolayer phase state on the surface of water when it was transferred to the solid substrate. The experimental I _D (t) dependence was compared with the time dependence of arachic monolayer surface coverage with sorbent molecules calculated by the Langmuir model. The conclusion was drawn that the model was capable of describing the sorption of ethanol vapor by the Langmuir-Blodgett arachic acid monolayer at low partial pressures p ≤ 0.05p ₀, where p ₀ is the saturated vapor pressure.     

Molecular Structure of Triphenylamine in the Gas Phase

The molecular structure of triphenylamine was studied by gas-phase electron diffraction in combination with ab initio calculations. It is found that in the gas phase at 160°C the molecule possesses C₃ symmetry. The principal geometric parameters are as follows (r _a structure): N-C 1.421(4), C-C_mean 1.399(1), C-H 1.123(2) Å, bond angles NCC 123.6(10)° and 117.2(7)°, and CNC 119.9(2)°. Torsion angles around C-N bonds are ?39° and ?45°. Phenyl groups are rotated by 48° from the position in which the C₃ axis lies in the phenyl ring plane.     

A New Sandwich Polyoxometalate Constructed from a Zn<Stack><Subscript>6</Subscript><Superscript>12+</Superscript></Stack> Hexagon Cluster Sandwiched by Two B-α-[BiW<Subscript>9</Subscript>O<Subscript>33</Subscript>]<Superscript>9−</Superscript>

A new sandwich polyoxometalate Na₄Zn₂[Zn₂(H₂O)₁₀(ZnCl)₆(B-α- BiW₉O₃₃)₂] · 40.5H₂O (1) has been obtained in aqueous solution and characterized by IR, UV, element analysis, TG and single-crystal X-ray analysis. Polyoxoanion 1 is composed of a Zn ₆ ¹²⁺ hexagon sandwiched by two [BiW₉O₃₃]^9? units, which is firstly observed in tungstobismutate. The crystal data for compound 1: Triclinic, space group P–1, a = 15.426(3) Å, b = 15.467(3) Å, c = 15.526(3) Å, α = 74.24(3)°, β = 64.37(3)°, γ = 60.73(3)°, V = 2905.3(1) ų, Z = 1.     

A Novel 3D Platinum–Thallium Coordination Polymer having Strong Metal–Metal Interactions

A new three-dimensional platinum(II)–thallium(I) coordination polymer [{Pt(pda)(NHCOtBu)₂}₄Tl₄][Pt(CN)₄]₂·2H ₂ O (pda = 1,2-propyldiamine) has been prepared from the direct reaction of [Tl₂Pt(CN)₄] and [Pt(pda)(NHCOtBu)₂] in water, and its structure was characterized by X-ray diffraction analysis. The compound crystallizes in monoclinic, space group Pn, a = 11.567(2) Å, b = 11.570(2) Å, c = 37.677(8)Å, β = 94.64(3)°, V = 5025.8(17) Å³, Z = 2, R1 = 0.0679 and wR2 = 0.1574 [I >  2σ (I)], Goodness-of-fit on F ² = 1.055. The compound exhibits a novel 3D network structure consisting of [Pt(CN)₄]^2? connected 1D infinite Pt–Tl–Pt–Tl chains via strong Pt–Tl bonds.