Thermodynamic evaluation and optimization of the (Na2SO4 + K2SO4 + Na2S2O7 + K2S2O7) system

A complete, critical evaluation of all phase diagram and thermodynamic data was performed for all phases of the (Na₂SO₄ + K₂SO₄ + Na₂S₂O₇ + K₂S₂O₇) system and optimized model parameters were obtained. The Modified Quasichemical Model in the Quadruplet Approximation was used for modelling the liquid phase. The model evaluates first- and second-nearest-neighbour short-range ordering, where the cations (Na⁺ and K⁺) are assumed to mix on a cationic sublattice, while anions were assumed to mix on an anionic sublattice. The Compound Energy Formalism was used for modelling the solid solutions of (Na,K)₂SO₄ and (Na,K)₂S₂O₇. The models can be used to predict the thermodynamic properties and phase equilibria in multicomponent heterogeneous systems. The experimental data from the literature were reproduced within experimental error limits.     

Partial exchange of the Li, Na and K alkaline cations in the HNi(PO4)·H2O layered compound

The exchange of the Li⁺(1), Na⁺(2) and K⁺(3) alkaline cations in the layered HNi(PO₄)·H₂O was carried out starting from a methanolic solution containing the Li(OH)·H₂O hydroxide for (1) and the M(OH) (M=Na and K) hydroxides together with the (C₆H₁₃NH₂)_0.75HNiPO₄·H₂O phases for (2) and (3). The compounds are stable until, approximately, 280 °C for (1) and 400 °C for phases (2) and (3), respectively. The IR spectra show the bands belonging to the water molecule and the (PO₄)³⁻ oxoanion. The diffuse reflectance spectra indicate the existence of Ni(II), d⁸, cations in slightly distorted octahedral geometry. The calculated Dq and Racah (B and C) parameters have a mean value of Dq=765, B=905 and , respectively, in accordance with the values obtained habitually for this octahedral Ni(II) cation. The study of the exchange process performed by X-ray powder diffraction indicates that the exchange of the Li⁺ cation in the lamellar HNi(PO₄)·H₂O phase is the minor rapid reaction, whereas the exchange of the Na⁺ and K⁺ cations needs the presence of the intermediate (C₆H₁₃NH₂)_0.75HNiPO₄·H₂O intercalate in order to obtain the required product with the sodium and potassium ions. The Scanning electronic microscopy (SEM) images show a mean size of particle of 5 μm. The Li⁺ exchanged compound exhibits small ionic conductivity (Ω cm⁻¹ is in the 10⁻⁸-10⁻⁹ range) probably restrained by the methanol solvent. Magnetic measurements carried out from 5 K to room temperature indicate antiferromagnetic coupling as the major interaction in the three phases. Notwithstanding the Li and K phases show a weak ferromagnetism at low temperatures.     

Solid–liquid metastable equilibria in the quaternary system Li2SO4 + MgSO4 + Na2SO4 + H2O at T = 263.15 K

Solubility in the liquid–solid metastable system Li₂SO₄ + MgSO₄ + Na₂SO₄ + H₂O at T = 263.15 K was studied using the isothermal evaporation method. Based on experimental data, dry-salt phase and water-phase diagrams of the system were plotted. The dry-salt phase diagram of the system includes one three-salt co-saturation point, three metastable solubility isotherm curves, and three crystallization regions corresponding to lithium sulphate monohydrate (Li₂SO₄·H₂O), epsomite (MgSO₄·7H₂O), and mirabilite (Na₂SO₄·10H₂O). Neither a solid solution nor double salts were found. Based on the extended Harvie–Weare (HW) model and its temperature-dependent equation, the values of the Pitzer parameters β⁽⁰⁾, β⁽¹⁾, β⁽²⁾, and C^Φ for Li₂SO₄, MgSO₄, and Na₂SO₄, the mixed ion-interaction parameters θ_Li,Na, θ_Li,Mg, θ_Na,Mg, ΨLi,Na,SO₄${\Psi }_{\text{Li,Na,S}{\text{O}}_4}$, ΨLi,Mg,SO₄${\Psi }_{\text{Li,Mg,S}{\text{O}}_4}$, and ΨNa,Mg,SO₄${\Psi }_{\text{Na,Mg,S}{\text{O}}_4}$, and the Debye–Hückel parameter A^Φ in the quaternary system at 263.15 K were obtained. The solubility of the quaternary system Li₂SO₄ + MgSO₄ + Na₂SO₄ + H₂O at T = 263.15 K was also calculated. A comparison between the calculated and experimental results shows that the predicted solubility agrees well with experimental data.     

The Al stabilized phase Li3−3xAlxBO3

The structure of an Al³⁺ stabilized phase Li_3−3xAl_xBO₃ (x≈0.18) was determined by means of single crystal X-ray diffraction. This phase crystallizes in space group P6₁22 or P6₅22, with lattice constants , and Z=6. The unit cell consists of six layers of BO₃ groups with Li⁺ cations distributing statistically on five crystallographic sites, none of which is fully occupied. The Li sites are close to each other and a three-dimensional network results when Li sites only within 1.65 Å are connected. Significant ionic conductivity was observed for this phase.     

Syntheses and structures of lithiated sulfones Li[CR(R′)SO2Ph] - C versus O bound lithium. [{Li{CH(Me)SO2Ph}(thf)}∞] - The structure of a C-bound derivative

Sulfones RCH(R′)SO₂Ph were reacted with n-BuLi in thf/n-hexane (R/R′ = H/Me, Me/Et, H/CH₂Ph) and toluene/n-hexane (R/R′ = Me/Ph) yielding under deprotonation Li[CR(R′)SO₂Ph] which reacted with Me₃SiCl and n-Bu₃SnCl forming the requisite trimethylsilyl and tri(n-butyl)tin substituted derivatives . Performing the reactions of RCH(R′)SO₂Ph with n-BuLi in n-hexane (instead of thf/n-hexane) and toluene/n-hexane, respectively, resulted in the precipitation of the organo lithium compounds Li[CR(R′)SO₂Ph] (1-4) which were isolated as strongly moisture-sensitive yellow powders in essentially quantitative yields. Their identities were confirmed by ¹H and ¹³C NMR spectroscopic measurements in thf-d₈. Solutions of each 1, 3, and 4 in thf/n-hexane and thf/n-pentane afforded crystals of each [{Li{CH(Me)SO₂Ph}(thf)}_∞] (1a), [{Li{CH(CH₂Ph)SO₂Ph}(thf)}_∞] (3a), and [{Li{CMe(Ph)SO₂Ph}(thf)₂}₂] (4a), respectively, whose structures were determined by single-crystal X-ray crystallography. The compounds 1a and 3a crystallize in 1D polymeric ladder-like structures. The strands of 1a are built-up by eight-membered Li₂C₂S₂O₂ rings having direct Li-C bonding interactions (Li-C 2.215(5) Å). The donor set of Li is completed by three oxygen atoms, one from the thf ligand and two from SO₂ groups of neighboring Li{CH(Me)SO₂Ph}(thf) entities. The strands of 3a are built-up of alternating Li₂S₂O₄ eight- and Li₂O₂ four-membered rings. Each lithium atom is coordinated to three oxygen atoms, two from O₂S(Ph)CHCH₂Ph groups and one from thf oxygen atom. There is no Li-C bonding. Compound 4a crystallizes in dimers consisting of eight-membered Li₂S₂O₄ rings in which the two lithium atoms are bridged by two O₂S(Ph)CHMePh groups. The coordination sphere of lithium is completed by two oxygen atoms of the thf ligands.     

Syntheses, structural and antimicrobial studies of a new N-allylamide of monensin A and its complexes with monovalent metal cations

A new N-allylamide of monensin A (M-AM2) was synthesized and its capacity to form complexes with Li⁺, Na⁺ and K⁺ cations was studied by ESI MS, ¹H and ¹³C NMR, FTIR spectroscopy and PM5 semi-empirical methods. ESI mass spectrometry indicates that M-AM2 forms complexes with Li⁺, Na⁺ and K⁺ of exclusively 1:1 stoichiometry which are stable up to cv=70 V, and the formation of 1:1 complexes between M-AM2 and Na⁺ cations is strongly favoured. Above cv=90 V we observe fragmentation of the respective complexes involving several dehydration steps. The spectroscopic studies show that the structures of the M-AM2 and its complexes with Li⁺, Na⁺ and K⁺ cations are stabilized by intramolecular hydrogen bonds in which the OH groups are always involved. The data also demonstrate that the CO amide group is engaged in the complexation process of each cation. However with the K⁺ cation we also found a structure in which this CO amide group does not participate in the complexation to a significant extent. The in vitro biological tests of M-AM2 amide show its good activity towards some strains of Gram-positive bacteria (Giz 13-19 mm; MIC 25-100 μg/ml).     

Magnetic and thermoelectric properties of layered LixNayCoO2

The magnetic, thermoelectric, and structural properties of Li_xNa_yCoO₂, prepared by intercalation and deintercalation chemistry from the thermodynamically stable phase Li_0.41Na_0.31CoO₂, which has an alternating Li/Na sequence along the c-axis, are reported. For the high Li-Na content phases Li_0.41Na_0.31CoO₂ and Li_0.40Na_0.43CoO₂, a sudden increase in susceptibility is seen below 50 K, whereas for Li_0.21Na_0.14CoO₂ an antiferromagnetic-like transition is seen at 10 K, in spite of a change from dominantly antiferromagnetic to dominantly ferromagnetic interactions with decreasing alkali content. The Curie constant decreases linearly with decreasing alkali content, at the same time the temperature-independent contribution to the susceptibility increases, indicating that as the Co becomes more oxidized the electronic states become more delocalized. Consistent with this observation, the low alkali containing phases have metallic-like resistivities. The 300 K thermopowers fall between 30 μV/K (x+y=0.31) and 150 μV/K (x+y=0.83).     

Crystal chemistry and ion-exchange properties of the layered uranyl iodate K[UO2(IO3)3]

Single crystals of the potassium uranyl iodate, K[UO₂(IO₃)₃] (1), have been grown under mild hydrothermal conditions. The structure of 1 contains two-dimensional sheets extending in the [ab] plane that consist of approximately linear UO₂²⁺ cations bound by iodate anions to yield UO₇ pentagonal bipyramids. There are three crystallographically unique iodate anions, two of which bridge between uranyl cations to create sheets, and one that is monodentate and protrudes in between the layers in cavities. K⁺ cations form long ionic contacts with oxygen atoms from the layers forming an eight-coordinate distorted dodecahedral geometry. These cations join the sheets together. Ion-exchange reactions have been carried out that indicate the selective uptake of Cs⁺ over Na⁺ or K⁺ by 1. Crystallographic data (193 K, MoKα, ): 1, orthorhombic, Pbca, a=11.495(1) Å, b=7.2293(7) Å, c=25.394(2) Å, Z=8, R(F)=1.95% for 146 parameters with 2619 reflections with I>2σ(I).     

Li ion diffusion in Li4Ti5O12 thin film electrode prepared by PVP sol-gel method

Li₄Ti₅O₁₂ thin films for rechargeable lithium batteries were prepared by a sol-gel method with poly(vinylpyrrolidone). Interfacial properties of lithium insertion into Li₄Ti₅O₁₂ thin film were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and potentiostatic intermittent titration technique (PITT). Redox peaks in CV were very sharp even at a fast scan rate of 50 mV s⁻¹, indicating that Li₄Ti₅O₁₂ thin film had a fast electrochemical response, and that an apparent chemical diffusion coefficient of Li⁺ ion was estimated to be 6.8×10⁻¹¹ cm² s⁻¹ from a dependence of peak current on sweep rates. From EIS, it can be seen that Li⁺ ions become more mobile at 1.55 V vs. Li/Li⁺, corresponding to a two-phase region, and the chemical diffusion coefficients of Li⁺ ion ranged from 10⁻¹⁰ to 10⁻¹² cm² s⁻¹ at various potentials. The chemical diffusion coefficients of Li⁺ ion in Li₄Ti₅O₁₂ were also estimated from PITT. They were in a range of 10⁻¹¹-10⁻¹² cm² s⁻¹.     

Synthesis and single crystal structures of ternary phosphides Li4SrP2 and AAeP (A=Li, Na; Ae=Sr, Ba)

Two new (NaSrP, Li₄SrP₂) and two known (LiSrP, LiBaP) ternary phosphides have been synthesized and characterized using single crystal X-ray diffraction studies. NaSrP crystallizes in the non-centrosymmetric hexagonal space group (#189, a=7.6357(3) Å, c=4.4698(3) Å, V=225.69(2) Å³, Z=3, and R/wR=0.0173/0.0268). NaSrP adopts an ordered Fe₂P structure type. PSr₆ trigonal prisms share trigonal (pinacoid) faces to form 1D chains. Those chains define large channels along the [001] direction through edge-sharing. The channels are filled by chains of PNa₆ face-sharing trigonal prisms. Li₄SrP₂ crystallizes in the rhombohedral space group (#166, a=4.2813(2) Å, c=23.437(2) Å, V=372.04(4) Å³, Z=3, and R/wR=0.0142/0.0222). In contrast to previous reports, LiSrP and LiBaP crystallize in the centrosymmetric hexagonal space group P6₃/mmc (#194, a=4.3674(3) Å, c=7.9802(11) Å, V=131.82(2) Å³, Z=2, and R/wR=0.0099/0.0217 for LiSrP; a=4.5003(2) Å, c=8.6049(7) Å, V=150.92(2) Å³, Z=2, and R/wR=0.0098/0.0210 for LiBaP). Li₄SrP₂, LiSrP, and LiBaP can be described as Li₃P derivatives. Li atoms and P atoms make a graphite-like hexagonal layer, . In LiSrP and LiBaP, Sr or Ba atoms reside between layers to substitute for two Li atoms of Li₃P, while in Li₄SrP₂, Sr substitutes only between every other layer.     

K2Li(NH2)3 and K2Na(NH2)3—synthesis and crystal structure of two crystal-chemically isotypic mixed-cationic amides

K₂Li(NH₂)₃ (1) was the only crystalline product obtained from the reaction of potassium with dilithium decahydro-closo-decaborate Li₂B₁₀H₁₀ in liquid ammonia at −38 °C. The compound crystallizes in the space group P4₂/m with Z=4, a=6.8720(5) Å, c=11.706(1) Å and V=552.81(7) Å³. The investigated crystal-chemically isotypic sodium compound K₂Na(NH₂)₃ (2) was merohedrally twinned and crystallized from a reaction mixture containing potassium and disodium decahydro-closo-decaborate Na₂B₁₀H₁₀ in liquid ammonia with a=7.0044(5) Å, c=12.362(1) Å and V=606.48(9) Å³. The compounds contain pairs of edge sharing tetraamidolithium or tetraamidosodium tetrahedra which are interconnected by potassium ions forming three-dimensional infinite networks.     

The structure of dehydrated (Li<Subscript>0.7</Subscript>Na<Subscript>0.3</Subscript>)-analcime: Trigonal deformation of the ANA framework and new low coordinated non-framework positions

The dehydrated form of (Li,Na)-substituted analcime, Li_1.30Na_0.53[Al_1.83Si_4.17O₁₂], has been prepared and investigated with single crystal X-ray diffraction: a = 32.167(6) Å, b = 18.551(2) Å, c = 11.693(2) Å; β = 90.06(1)°, V = 6978(1) ų, Z = 24, space group C2. The structure was analyzed through considering the aluminosilicate framework as a system of tubes composed from corrugated 6-membered rings joint by triples of tetrahedra. Volume decrease by 6.5% and trigonal distortion of the structure are explained by the localization of the non-framework cations in new unusual positions. On dehydration of Li, Na-analcime, 67% of Na⁺ and 20% of Li⁺ migrated from the standard M-positions at the periphery of the tubes into essentially different positions Na^W and Li^L situated on the axes of the tubes. Among the total of the fixed tube positions— 12Na^W and 16Li^L — one half is aggregated in the tubes parallel to [001] and has a planar three-fold coordination by framework O-atoms. The configuration and cation population of the tubes in other directions follow the motif of the “basic” system.     

Carbon coated Na3V2(PO4)3 as novel electrode material for sodium ion batteries

A Na₃V₂(PO₄)₃ sample coated uniformly with a layer of 6 nm carbon has been successfully synthesized by a one-step solid state reaction. This material shows two flat voltage plateaus at 3.4 V vs. Na⁺/Na and 1.63 V vs. Na⁺/Na in a nonaqueous sodium cell. When the Na₃V₂(PO₄)₃/C sample is tested as a cathode in a voltage range of 2.7-3.8 V vs. Na⁺/Na, its initial charge and discharge capacities are 98.6 and 93 mAh/g. The capacity retention of 99% can be achieved after 10 cycles. The electrode shows good cycle performance and moderate rate performance. When it is tested as an anode in a voltage range of 1.0-3.0 V vs. Na⁺/Na, the initial reversible capacity is 66.3 mAh/g and the capacity of 59 mAh/g can be maintained after 50 cycles. These preliminary results indicate that Na₃V₂(PO₄)₃/C is a new promising material for sodium ion batteries.     

Aluminum phosphate dispersed on a cellulose acetate fiber surface: Preparation, characterization and application for Li, Na and K separation

Cellulose acetate fibers with supported highly dispersed aluminum phosphate were prepared by reacting aluminum-containing cellulose acetate (Al₂O₃=3.5 wt.%; 1.1 mmol g⁻¹ aluminum atom per gram of the material) with phosphoric acid. Solid-state NMR spectra (CPMAS ³¹P NMR) data indicated that HPO₄²⁻ is the species present on the fiber surface. The specific concentration of acidic centers, determined by ammonia gas adsorption, is 0.50 mmol g⁻¹. The ion exchange capacities for Li⁺, Na⁺ and K⁺ ions were determined from ion exchange isotherms at 298 K and showed the following values (in mmol g⁻¹): Li⁺=0.03, Na⁺=0.44 and K⁺=0.50. The H⁺/Li⁺ exchange corresponds to the model of the ideal ion exchange with a small value of the corresponding equilibrium constant K=1.1×10⁻². Due to the strong cooperative effect, the H⁺/Na⁺ and H⁺/K⁺ ion exchange is non-ideal. These ion exchange equilibria were treated with the use of models of fixed bi- or tridentate centers, which consider the surface of the sorbent as an assemblage of polyfunctional sorption centers. Both the observed ion exchange capacities with respect to the alkaline metal ions and the equilibrium constants were discussed by taking into consideration the sequence of the ionic hydration radii for Li⁺, Na⁺ and K⁺. The matrix affinity order for the ions decreases as the hydration radii of the cations increase, i.e. Li⁺>Na⁺>K⁺. The high values of the separation factors S_Na⁺/Li⁺ and S_K⁺/Li⁺ (up to several hundred) provide quantitative separation of Na⁺ and K⁺ from Li⁺ from a mixture containing these three ions.     

Syntheses, crystal structures and spectroscopic properties of Ag2Nb[P2S6][S2] and KAg2[PS4]

Ag₂Nb[P₂S₆][S₂] (1) was obtained from the direct solid state reaction of Ag, Nb, P₂S₅ and S at 500 °C. KAg₂[PS₄] (2) was prepared from the reaction of K₂S₃, Ag, Nd, P₂S₅ and extra S powder at 700 °C. Compound 1 crystallizes in the orthorhombic space group Pnma with a=12.2188(11), b=26.3725(16), c=6.7517(4) Å, V=2175.7(3) Å³, Z=8. Compound 2 crystallizes in the non-centrosymmetric tetragonal space group with lattice parameters a=6.6471(7), c=8.1693(11) Å, V=360.95(7) Å³, Z=2. The structure of Ag₂Nb[P₂S₆][S₂] (1) consists of [Nb₂S₁₂], [P₂S₆] and new found puckered [Ag₂S₄] chains which are along [001] direction. The Nb atoms are located at the center of distorted bicapped trigonal prisms. Two prisms share square face of two [S₂²⁻] to form one [Nb₂S₁₂] unit, in which Nb-Nb bond is formed. The [Nb₂S₁₂] units share all S²⁻ corners with ethane-like [P₂S₆] units to form 14-membered rings. The novel puckered [Ag₂S₄] chains are composed of distorted [AgS₄] tetrahedra and [AgS₃] triangles that share corners with each other. These chains are connected with [P₂S₆] units and [Nb₂S₁₂] units to form three-dimensional frame work. The structural skeleton of 2 is built up from [AgS₄] and [PS₄] tetrahedra linked by corner-sharing. The three-dimensional anionic framework contains orthogonal, intersecting tunnels directed along [100] and [010]. This compound possesses a compressed chalcopyrite-like structure. The structure is compressed along [001] and results from eight coordination sphere for K⁺. Both compounds are characterized with UV/vis diffuse reflectance spectroscopy and compound 1 with IR and Raman spectra.     

Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A2(UO2)3(VO4)2O (A=Li, Na)

The uranyl vanadates A₂(UO₂)₃(VO₄)₂O (A=Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from chains of edge-shared U(2)O₇ pentagonal bipyramids alternatively parallel to - and -axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet parallel to (001), formed by U(1)O₆ square bipyramids connected by VO₄ tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates non-intersecting channels running down the - and -axis formed by empty face-shared oxygen octahedra, the Li⁺ ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li⁺ ion together with the full occupancy explain the low conductivity of Li₂(UO₂)₃(VO₄)₂O compared with that of Na(UO₂)₄(VO₄)₃ containing the same type of channels half occupied by Na⁺ ions in the octahedral sites.Crystallographic data for Li₂(UO₂)₃(VO₄)₂O: tetragonal, space group I41/amd, , , , Z=4, ρ_mes=5.32(2) g/cm³, ρ_cal=5.36(3) g/cm³, full-matrix least-squares refinement basis on F² yielded, R₁=0.032, wR₂=0.085 for 37 refined parameters with 364 independent reflections with I?2σ(I).     

Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type NaxTi2O4 with 0.558<x<1

Single crystals of calcium ferrite CaFe₂O₄-type NaTi₂O₄ having millimeter-sized needle shapes were synthesized by a reaction of Na metal and TiO₂ in a sealed iron vessel at 1473 K. Sodium-deficient Na_xTi₂O₄ single crystals with 0.558<x<1 were successfully synthesized by a topotactic oxidation reaction using NaTi₂O₄ single crystals as parent materials. The crystal structures of Na_xTi₂O₄ with x=0.970, 0.912, 0.799, 0.751, 0.717, 0.686, 0.611, and 0.558 were determined by the single-crystal X-ray diffraction method. The basic framework constructed by the Ti1O₆ and Ti2O₆ double rutile chains was maintained in these Na_xTi₂O₄ compounds. Based on the results of bond valence analysis, we speculated that the Ti1 sites are preferentially occupied by Ti³⁺ cations over the compositional range of 0.8<x<1, while both the Ti1 and Ti2 sites are randomly occupied by Ti³⁺ and Ti⁴⁺ cations at x=0.558. Magnetic susceptibility data indicated that the broad maximum around 40 K observed in as-grown NaTi₂O₄ is suppressed by an Na deficiency and vanishes in Na_0.717Ti₂O₄. The electrical resistivity increased with the Na deficiency; however, it was still semiconductive in Na_0.799Ti₂O₄.     

Synthesis, structure, optical properties, and electronic structure of NaLiCdS2

The new compound NaLiCdS₂ has been synthesized by the reaction of Cd and a Li₂S/S/Na₂S flux at 773 K. This compound, which has the Ce₂O₂S structure type, crystallizes with one formula unit in space group P3¯m1 of the trigonal system in a cell at T=153 K with a=4.1320(3) Å and c=6.8666(11) Å. The structure consists of two-dimensional layers stacked perpendicular to the [001] direction. The two-dimensional layers are formed by corner-sharing LiS₄ or CdS₄ tetrahedra. The Na atoms are between these layers. Li incorporation in the compound is confirmed by an SIMS chemical composition map and by ICP measurements. The Li and Cd atoms are disordered in the crystal structure. First-principles calculations show that the optical excitations arise primarily from S→Cd charge-transfer transitions at 1.0 eV (very weak) and 2.4 eV (strong). Calculations also indicate that Na contributions around the Fermi level are significant. Polarized single-crystal optical measurements indicate an indirect optical band gap of 2.37 eV for light perpendicular to the (001) crystal face, in good agreement with theory. The compound NaLiZnS₂ has also been synthesized and is found to be isostructural with NaLiCdS₂.