Composition K0 Research Articles

Influence of Synthesis Conditions on the Capacitance Performance of Hydrothermally Prepared MnO2 for Carbon Xerogel-Based Solid-State Supercapacitors

In this study, the potential to modify the phase structure and morphology of manganese dioxide synthesized via the hydrothermal route was explored. A series of samples were prepared at different synthesis temperatures (100, 120, 140, and 160 °C) using KMnO4 and MnSO4·H2O as precursors. The phase composition and morphology of the materials were analyzed using various physicochemical methods. The results showed that, at the lowest synthesis temperature (100 °C), an intercalation compound with composition K1.39Mn3O6 and a very small amount of α-MnO2 was formed. At higher temperatures (120–160 °C), the amount of α-MnO2 increased, indicating the formation of two clearly distinguished crystal structures. The sample obtained at 160 °C exhibited the highest specific surface area (approximately 157 m2/g). These two-phase (α-MnO2/K1.39Mn3O6) materials, synthesized at the lowest and highest temperatures, respectively, and containing an appropriate amount of carbon xerogel, were tested as active mass for positive electrodes in a solid-state supercapacitor, using a Na+-form Aquivion® membrane as the polymer electrolyte. The electrochemical evaluation showed that the composite with the higher specific surface area, containing 75% manganese dioxide, demonstrated improved characteristics, including 96% capacitance retention after 5000 charge/discharge cycles and high energy efficiency (approximately 99%). These properties highlight its potential for application in solid-state supercapacitors.

K0.72Na1.71Ca5.79Si6O19 - the first oligosilicate based on [Si6O19]-hexamers and its stability compared to cyclosilicates.

Synthesis experiments were conducted in the quaternary system K2O-Na2O-CaO-SiO2, resulting in the formation of a previously unknown compound with the composition K0.72Na1.71Ca5.79Si6O19. Single crystals of sufficient size and quality were recovered from a starting mixture with a K2O:Na2O:CaO:SiO2 molar ratio of 1.5:0.5:2:3. The mixture was confined in a closed platinum tube and slowly cooled from 1150°C at a rate of 0.1°C min-1 to 700°C before being finally quenched in air. The structure has tetragonal symmetry and belongs to space group P4122 (No. 91), with a = 7.3659 (2), c = 32.2318 (18) Å, V = 1748.78 (12) Å3, and Z = 4. The silicate anion consists of highly puckered, unbranched six-membered oligomers with the composition [Si6O19] and point group symmetry 2 (C2). Although several thousands of natural and synthetic oxosilicates have been structurally characterized, this compound is the first representative of a catena-hexasilicate anion, to the best of our knowledge. Structural investigations were completed using Raman spectroscopy. The spectroscopic data was interpreted and the bands were assigned to certain vibrational species with the support of density functional theory at the HSEsol level of theory. To determine the stability properties of the novel oligosilicate compared to those of the chemically and structurally similar cyclosilicate combeite, we calculated the electronegativity of the respective structures using the electronegativity equalization method. The results showed that the molecular electronegativity of the cyclosilicate was significantly higher than that of the oligostructure due to the different connectivities of the oxygen atoms within the molecular units.

Calcium-Pillar Boosting Smooth Phase Transition in Potassium Vanadate Nanobelts toward Superior Cycling Performance in Potassium-Ion Batteries.

The depletion of lithium resources has prompted exploration into alternative rechargeable energy storage systems, and potassium-ion batteries (PIBs) have emerged as promising candidates. As an active cathode material for PIBs, potassium vanadate (KxV2O5) usually suffers from structural damage during electrochemical K-ion insertion/extraction and hence leading to unsatisfactory cycling performance. Here, we introduce Ca2+ ions as pillars into the potassium vanadate to enhance its structural stability and smooth its phase transition behavior. The additional Ca2+ not only stabilizes the layered structure but also promotes the rearrangement of interlayer ions and leads to a smooth solid-solution phase transition. The optimal composition K0.36Ca0.05V2O5 (KCVO) exhibits outstanding cyclic stability, delivering a capacity of ∼90 mA h g-1 at 20 mA g-1 with negligible capacity decay even after 700 cycles at 500 mA g-1. Theoretical calculations indicate lower energy barriers for K+ diffusion, promoting rapid reaction kinetics. The excellent performances and detailed investigations offer insights into the structural regulation of layered vanadium cathodes.

ANALYSIS OF THE DENSITY AND COMBUSTION RATE OF BRIQUETTE BASED ON THE COMPOSITION OF PEANUT SHELL AND COCONUT SHELL INGREDIENTS

The study's purpose was to analyze the density value and the burning rate of briquettes made from a combination of peanut shell and coconut shell ingredients with a fixed amount of starch adhesive concentration. The briquette making involves processing peanut shells and coconut shells, grinding and 60 mesh sifting, mixing with adhesive, printing, and drying in an oven (1200C for ± 30 minutes). The samples tested were the composition of peanut shells (K) and coconut shells (T). The combination of two briquette materials has the same mass of 100 gr for each sample. The samples were made with several compositions, namely K1 (T = 90, K = 10), K2 (T = 80, K = 20), K3 (T = 70, K = 30), K4 (T = 60, K = 40 ), K5 ( T = 50, K = 50), K6 ( T = 40, K = 60), K7 ( T = 30, K = 70). The results showed that the highest density value was obtained from the K7 composition, which means it is composed of 30 gr coconut shell and 70 gr peanut shell with a density value of 0.292 gr/cm3 and the lowest density value obtained from the K3 composition, which means it is composed of 70 gr coconut shell and 30 grams of peanut skin with a density value of 0.170 gr/cm3. The longest flame time of the briquettes, until they go out and turn into ashes, is obtained from composition K1, which means it is composed of 90 grams of coconut shell and 10 grams of peanut shell with a flame time of 88 minutes, and the shortest time of the burning of briquettes until it goes out and turns into ashes is obtained from composition K5 which composed of 50 grams of coconut shell and 50 grams of peanut shell with a burning time of 57 minutes. The longest burning rate of briquettes, until they were extinguished and turned into ashes, was obtained from samples K3 and K5 with a burning rate of 125.6 cm3/minute, then the shortest burning rate of briquettes until they were extinguished and turned into ashes was obtained from samples K4 with a burning rate of 108.518 cm3/minute.

Synthesis and Stabilization of Crystal Hydrate Modification SrSO4⋅0.5H2O

A method has been developed for the synthesis of the metastable trigonal modification SrSO4⋅0.5H2O, isostructural to the well-known CaSO4⋅0.5H2O modification (space group P3121). Frozen solutions of NaCl in water have been proposed as a precursor in the crystallization of SrSO4⋅0.5H2O. The SrSO4⋅0.5H2O structure can be stabilized by isovalent substitution of calcium ions for strontium ions or by aliovalent substitution of potassium and lanthanum ions for strontium ions. The compound of composition K0.25La0.25Sr0.5(SO4)⋅0.5H2O has been synthesized as an example of the stabilized SrSO4⋅0.5H2O modification. The unit cell parameters have been determined and refined. A model of the structure of SrSO4⋅0.5H2O with a statistical distribution of potassium, lanthanum, and strontium atoms over the positions of Ca atoms in the well-known СаSO4⋅0.5H2O structure has been proposed.

MgNb2 O6 Modified K0.5 Na0.5 NbO3 Eco-Piezoceramics: Scalable Processing, Structural Distortion and Complex Impedance at Resonance.

In this work, piezoceramics of the lead‐free composition K0.5Na0.5NbO3 with an increasing amount of MgNb2O6 (0, 0.5, 1, 2 wt.%) were prepared through conventional solid‐state synthesis and sintered in air atmosphere at 1100 °C. The effect of magnesium niobate addition on structure, microstructure and piezoelectric properties was evaluated. The ceramics maintain the orthorhombic Amm2 phase for all compositions, while an orthorhombic Pbcm secondary phase was found for increasing the concentration of MgNb2O6. Our results show that densification of these ceramics can be significantly improved up to 94.9 % of theoretical density by adding a small amount of magnesium‐based oxide (1 wt.%). Scanning electron microscopy morphology of the 1 wt.% system reveals a well‐packed structure with homogeneous grain size of ∼2.72 μm. Dielectric and piezoelectric properties become optimal for 0.5–1.0 wt.% of MgNb2O6 that shows, with respect to the unmodified composition, either higher piezoelectric coefficients, lower anisotropy and relatively low piezoelectric losses (d33=97 pC N−1; d31=−36.99 pC N−1 and g31=−14.04×10−3 mV N−1; Qp(d31)=76 and Qp(g31)=69) or enhanced electromechanical coupling factors (kp=29.06 % and k31=17.25 %).

Fluoride ion conductivity of solid solutions KxPb0.86-xSn1.14F4-x

The electrical conductivity of solid solutions with tetragonal syngony formed in 0.86(xKF?(1?x)PbF2)?1.14SnF2 systems has been studied by 19F- -NMR and impedance spectroscopy. It was found that the Pb0.86Sn1.14F4 phase is characterized by better values of fluoride-ion conductivity than the ?-PbSnF4 compound. It was found that the substitution of Pb2+ by K+ up to ? = 0.07 in the structure of Pb0.86Sn1.14F4 contributes to increase in electrical conductivity by an order of magnitude relative to the original Pb0.86Sn1.14F4. The sample of composition K0.03Pb0.83Sn1.14F3.97 has the highest electrical conductivity (?600 = = 0.38 S cm-1, ?330 = 0.01 S cm-1). The fluoride anions in the synthesized samples of KxPb0.86-xSn1.14F4-x solid solutions occupy three structurally nonequivalent positions. It is shown that with increasing temperature, there is a redistribution of fluorine anions between positions in the anion lattice, which results in an increase in the concentration of highly mobile fluoride ions, which determine the electrical conductivity of the samples.

Rippite, K2(Nb,Ti)2(Si4O12)O(O,F), a New K-Nb-Cyclosilicate from Chuktukon Carbonatite Massif, Chadobets Upland, Krasnoyarsk Territory, Russia

Rippite K2(Nb,Ti)2(Si4O12)(O,F)2, a new K-Nb-cyclosilicate, has been discovered in calciocarbonatites from the Chuktukon massif (Chadobets upland, SW Siberian Platform, Krasnoyarsk Territory, Russia). It was found in a primary mineral assemblage, which also includes calcite, fluorcalciopyrochlore, tainiolite, fluorapatite, fluorite, Nb-rich rutile, olekminskite, K-feldspar, Fe-Mn–dolomite and quartz. Goethite, francolite (Sr-rich carbonate–fluorapatite) and psilomelane (romanèchite ± hollandite) aggregates as well as barite, monazite-(Ce), parisite-(Ce), synchysite-(Ce) and Sr-Ba-Pb-rich keno-/hydropyrochlore are related to a stage of metasomatic (hydrothermal) alteration of carbonatites. The calcite–dolomite coexistence assumes crystallization temperature near 837 °C for the primary carbonatite paragenesis. Rippite is tetragonal: P4bm, a = 8.73885(16), c = 8.1277(2) Å, V = 620.69(2) Å3, Z = 2. It is closely identical in the structure and cell parameters to synthetic K2Nb2(Si4O12)O2 (or KNbSi2O7). Similar to synthetic phase, the mineral has nonlinear properties. Some optical and physical properties for rippite are: colorless; Mohs’ hardness—4–5; cleavage—(001) very perfect, (100) perfect to distinct; density (meas.)—3.17(2) g/cm3; density (calc.)—3.198 g/cm3; optically uniaxial (+); ω = 1.737-1.739; ε = 1.747 (589 nm). The empirical formula of the holotype rippite (mean of 120 analyses) is K2(Nb1.90Ti0.09Zr0.01)[Si4O12](O1.78OH0.12F0.10). Majority of rippite prismatic crystals are weakly zoned and show Ti-poor composition K2(Nb1.93Ti0.05Zr0.02)[Si4O12](O1.93F0.07). Raman and IR spectroscopy, and SIMS data indicate very low H2O content (0.09–0.23 wt %). Some grains may contain an outermost zone, which is enriched in Ti (+Zr) and F, up to K2(Nb1.67Ti0.32Zr0.01)[Si4O12](O1.67F0.33). It strongly suggests the incorporation of (Ti,Zr) and F in the structure of rippite via the isomorphism Nb5+ + O2− → (Ti,Zr)4+ + F1−. The content of a hypothetical end-member K2Ti2[Si4O12]F2 may be up to 17 mol. %. Rippite represents a new structural type among [Si4O12]-cyclosilicates because of specific type of connection of the octahedral chains and [Si4O12]8− rings. In structural and chemical aspects it seems to be in close with the labuntsovite-supergroup minerals, namely with vuoriyarvite-(K), K2(Nb,Ti)2(Si4O12)(O,OH)2∙4H2O.

Effect of Electrolyte Anion on Electrochemical Behavior of Nickel Hexacyanoferrate Electrode in Aqueous Sodium-Ion Batteries

Nickel hexacyanoferrate (NiHCF) has a three-dimensional open framework structure, excellent long-cycling stability and rate performance as a cathode for aqueous sodium-ion batteries. However, the specific capacity of NiHCF is lower than that of present cathodes for aqueous batteries. A sodium-ion electrolyte was explored to achieve optimum capacity with NiHCF. Powder-type NiHCF was fabricated by coprecipitation with the atomic composition K0.065Ni1.44Fe(CN)6·4.4H2O. The presence of Fe vacancies in the atomic composition is attributable to the inclusion of coordinating and zeolitic water during coprecipitation. Two sodium-ion electrolytes, 1 M Na2SO4 and 1 M NaNO3, were employed to analyze the electrochemical behavior of the NiHCF electrode. Identical redox potentials to 0.58 V (vs. NHE) were measured in both electrolytes. However, a lower overpotential was observed in NaNO3 compared to Na2SO4 as a result of the smaller interfacial charge transfer resistance. The lower charge transfer resistance in the NaNO3 solution produced a higher specific capacity of 57 mAh g<sup>-1</sup> (1 C-rate) and the superior capacity retention of 46.6% at 20 C-rate. The anion in the aqueous electrolyte changed the charge transfer resistance at the electrode/electrolyte interface, confirming the electrolyte anion has a crucial effect on the charge capacity and rate performance of NiHCF.

Serendipitous formation and characterization of K2[Pd(NO3)4]·2HNO3

Abstract A potassium tetranitratopalladate(II) with the composition K2[Pd(NO3)4] · 2HNO3 was synthesized by a simple solvothermal process in a glass ampoule. The new compound crystallizes in the monoclinic space group P21 /c (no. 14) with the lattice parameters a = 1017.15(4), b = 892.94(3), c = 880.55(3) Å, and β = 98.13(1)° (Z = 2). The crystal structure of K2[Pd(NO3)4] · 2HNO3 reveals isolated complex [Pd(NO3)4]2− anions, which are surrounded by eight potassium cations and four HNO3 molecules. The complex anions and the cations are associated in layers which are separated by HNO3 molecules. K2[Pd(NO3)4] · 2HNO3 can thus be regarded as a HNO3 intercalation variant of β-K2[Pd(NO3)4]. The characterization is based on single-crystal X-ray and powder X-ray diffraction.

First investigations on the quaternary system Na2O-K2O-CaO-SiO2: synthesis and crystal structure of the mixed alkali calcium silicate K1.08Na0.92Ca6Si4O15

In the course of an exploratory study on the quaternary system Na2O-K2O-CaO-SiO2 single crystals of the first anhydrous sodium potassium calcium silicate have been obtained from slow cooling of a melt in the range between 1250 and 1050 °C. Electron probe micro analysis suggested the following idealized molar ratios of the oxides for the novel compound: K2O:Na2O:CaO:SiO2 = 1:1:12:8 (or KNaCa6Si4O15). Single-crystal diffraction measurements on a crystal with chemical composition K1.08Na0.92Ca6Si4O15 resulted in the following basic crystallographic data: monoclinic symmetry, space group P 21/c, a = 8.9618(9) Å, b = 7.3594(6) Å, c = 11.2453(11) Å, β= 107.54(1)°, V = 707.2(1) Å3, Z = 2. Structure solution was performed using direct methods. The final least-squares refinement converged at a residual of R(|F|) = 0.0346 for 1288 independent reflections and 125 parameters. From a structural point of view, K1.08Na0.92Ca6Si4O15 belongs to the group of mixed-anion silicates containing [Si2O7]- and [SiO4]-units in the ratio 1:2. The mono- and divalent cations occupy a total of four crystallographically independent positions located in voids between the tetrahedra. Three of these sites are exclusively occupied by calcium. The fourth site is occupied by 54(1)% K and 46%(1) Na, respectively. Alternatively, the structure can be described as a heteropolyhedral framework based on corner-sharing silicate tetrahedra and [CaO6]-octahedra. The network can build up from kröhnkite-like [Ca(SiO4)2O2]-chains running along [001]. A detailed comparison with other A2B6Si4O15-compounds including topological and group-theoretical aspects is presented.

Preparation and Characterization of Borosilicate Glass Waste Form for Immobilization of HLW from WWER Spent Nuclear Fuel Reprocessing

ABSTRACTBorosilicate glassy materials for immobilization of HLW from Russian WWER (PWR) spent nuclear fuel reprocessing were designed, synthesized in a resistive furnace, and characterized by XRD, SEM/EDS, and FTIR spectroscopy. Chemical durability was determined by PCT-A procedure and compared to EPA glass and reference data. The glasses with 20 and 25 wt.% waste loading were found to be X-ray amorphous, homogeneous and chemically durable. Glass network formally had a relatively low degree of connectedness that was increased due to embedding of different structural groups thus improving chemical durability. Boron is present primarily in trigonal oxygen coordination. The glasses with 40-45 wt.% waste loading contained minor britholite phase concentrating rare earth elements and as expected trivalent actinides. Glassy product with up to 30 wt.% waste loading was also produced by cold crucible inductive melting at the IPCE RAS lab-scale unit equipped with 56 mm inner diameter copper cold crucible and energized from a 10 kW/5.28 MHz generator. The product was composed of vitreous phase and minor britholite with average composition K0.39Sr1.99Fe0.16Nd5.50Si7.96O26.60.

A New Potassium Intercalation Compound of 3R-Nb1.1S2and its Superconducting Hydrated Derivative Synthesized via Soft Chemistry Strategy

A new polymorph of potassium intercalation compound of 3R-Nb1.1S2 with chemical composition K0.77Nb1.1S2 was synthesized for the first time by a facile solution-phase method. Its structure was comprehensively characterized by powder XRD and high-resolution TEM. Furthermore, its hydrated derivatives KxNb1.1S2• yH2O were synthesized via soft chemistry strategy using etching agents of ethanol, water and an I2/CH3CN solution, respectively. Superconducting transition at 4.0 K was observed for the product with the doping content x=0.12. While superconductivity disappeared in products KxNb1.1S2• yH2O (x=0.48 and 0.35) which displayed a metal-to-semiconductor transition at low temperature. In addition, the XPS analysis revealed an upward shift in the Fermi level in K0.12Nb1.1S2• yH2O compared with the host or K0.77Nb1.1S2.

Prospective Application of Copper Hexacyanoferrate for Capturing Dissolved Ammonia

Copper hexacyanoferrate (CuHCF) with the composition of K0.76Cu[Fe(CN)6]0.69·3.6H2O was prepared and studied for its potential on recovering dissolved ammonia. Fast adsorption kinetics and the least impact of coexisting sodium ion, which is abundant in environmental waters, are noteworthy. From the solution of ammonium chloride in pure water, the material showed almost constant adsorption in the pH range of 2 to 7, a slight increment was observed until pH 9, and a decreasing tendency was observed afterward. This is because of the decreasing concentration of ammonium ion starting at pH 8. Interestingly, FT-IR taken after adsorption at pH 11 showed peaks of both ammonium and ammonia forms, which reinforces the applicability of the material for not only the ammonium ion but also the overall ammonia in solution phase. Results show potassium–ammonium ion exchange as the major process behind the selective adsorption of ammonium. However, the mechanism of adsorption of the NH3 form is yet to be known. CuHCF hold...

Electrophysical Properties of Ceramic Articles Based on Potassium Polytitanate Nanopowder Modified By Iron Compounds

The effect of the firing temperature on the phase composition and electrophysical properties of ceramic articles obtained on the basis of compacted powders of the product of the interaction of potassium polytitanate and water solutions of iron (III) salts is investigated. When fired at temperature near 700°C (optimal value) the ceramic has pronounced properties of a solid electrolyte and is formed on the basis of a solid solution with the composition K1.46Ti7.2Fe0.8O16. At higher temperatures this solid solution becomes unstable and partially decomposes.

Performance of K0.5 Na0.5 NbO3 (KNN)‐based Lead‐free Piezoelectric Materials in Active Vibration Control

Lead‐free ceramics in the composition of K0.5 Na0.5 NbO3 (KNN) are reported to be promising for piezoelectric application. This family of material has comparable piezoelectric properties to that of existing lead‐based ceramics. Present study deals with performance evaluation of KNN based materials for active vibration control. Finite element method is used to simulate the performance of these materials. Interestingly, K0.5 Na0.5 NbO3 ‐LiSbO3‐CaTiO3 (KNN‐LS‐CT) demonstrated better vibration control behavior than that of conventional lead‐based compounds. These materials are also reported to be temperature insensitive (−50 to 200°C) for piezoelectric properties viewpoints.

Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

Lead-free potassium lithium tantalate niobate single crystals with the composition of K0.95Li0.05Ta1−xNbxO3 (abbreviated as KLTN, x=0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x=0.60 composition, kt≈70%, k31≈70%, k33≈77%, d31≈230pC/N, d33≈600pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

Sintering Temperature Effect on Ferroelectric and Piezoelectric Properties of Lead-Free Piezoelectric (K<sub>0.5</sub>Na<sub>0.5</sub>)NbO<sub>3</sub> Ceramics

Lead-free potassium sodium niobate ceramic, with the nominal composition of K0.5Na0.5NbO3, were synthesized by conventional solid state sintering, and its dielectric, ferroelectric, and piezoelectric properties were characterized as a function of sintering temperature. The orthorhombic to tetragonal phase transition (TO-T) temperature of K0.5Na0.5NbO3 ceramic sample was about 220°C, and its Curie temperature was about 420°C. The high bulk density was obtained for all compositions by solid state sintering in air. Bulk density was increased with temperature and it reached to 4.4 g/cm3. The K0.5Na0.5NbO3 ceramic sample sintered at 1100°C was optimized densification properties. In addition, the ferroelectric loop and dielectric characteristics dependence of different sintering temperature for K0.5Na0.5NbO3 ceramic sample was obtained. Finally, we found that the piezoelectric constant (d33) was 160 pC/N, high remanent polarization (Pr) was 33mC/cm2, and high electromechanical coupling coefficients (kP) was about of 45%.

Determining the Stoichiometry of (K,Na)NbO3 Using Optimized Energy-Dispersive X-Ray Spectroscopy and Electron Energy-Loss Spectroscopy Analyses in a Transmission Electron Microscope

This paper describes an optimized analytical procedure for determining the composition of alkaline niobate-based lead-free piezoceramics by energy-dispersive X-ray spectroscopy (EDXS) in a transmission electron microscope (TEM). To discriminate the material-specific composition from the artifacts introduced during the EDXS/TEM analyses, the effects of radiation damage and the absorption of the characteristic X-ray lines were studied in detail. The optimized, quantitative EDXS analysis was tested on sodium potassium niobate with the nominal composition K0.5Na0.5NbO3 (KNN) by applying KNbO3 and NaNbO3 as standards. The results obtained indicate that KNbO3 is more radiation sensitive than NaNbO3. A similar degradation was confirmed in KNN, where the loss of potassium was higher than that of sodium. In addition, the degradation of the KNN was associated with a severe oxygen loss and the reduction of niobium. To achieve highly reliable, quantitative analyses and to preserve good counting statistics, the optimum conditions for the EDXS/TEM analyses were found at an electron dose rate of 0.4 pA/nm2 and an acquisition time of around 200 s in the specimen thickness range between 30 and 200 nm.

Modulated structure of nepheline

The incommensurately modulated structure of a natural nepheline of composition K(0.54)Na(3.24)Ca(0.03)Al(3.84)Si(4.16)O(16) has been determined in superspace. The compound crystallizes in the trigonal centered superspace group X3(00γ)0 with γ = 0.2048 (10), X = (0, 0, 0, 0), (1/3, 2/3, 0, 2/3), (2/3, 1/3, 0, 1/3), a = 17.2889 (8) and c = 8.3622 (10) Å. The structure is characterized by a framework of corner-connected (Al,Si)O(4) tetrahedra. The additional cations are incorporated in two different types of channels of the framework. All atoms in the structure are displacively modulated with amplitudes below 0.1 Å. The modulation can be well described taking into account harmonics of first order only. Atomic positions in the smaller channels of the framework are fully occupied by Na(+). Cationic positions in the larger channel are occupationally modulated, yet the variation of electron density as a function of the internal coordinate t is very small and indicates that the incorporation of different types of cations (K(+), Na(+), Ca(2+)) and vacancies is realised in a highly disordered way. Average T-O distances indicate a nearly complete Al/Si ordering in the tetrahedral framework. A large part of the O atoms are approximated by split-atom positions, which are additionally affected by occupational modulation resulting in a high degree of disorder in the modulated structure. Occupational probabilities for the split-atom positions are complementary. Occupational modulations of the cations in the larger channels and the O atoms of the tetrahedral framework are coupled and correlations between occupational and displacive modulations exist.