Packing Structure Research Articles

Automated Parametrization Approach for Coarse-Graining Soil Organic Matter Molecules.

Investigating the molecular structure of soil organic matter (SOM), along with its intramolecular interactions and interactions with other soil components and xenobiotics, is essential due to its ecological importance. However, the complexity and heterogeneity of SOM present significant challenges for systematic studies. While experimental methods are commonly employed, atomistic simulations provide a complementary approach to exploring molecular-level processes. The Vienna Soil Organic Matter Modeler 2 (VSOMM2) facilitates the construction of molecular models of SOM systems with various compositions at the atomistic scale, which can then be examined through molecular dynamics (MD) simulations. This study introduces a parametrization strategy that enables the conversion of VSOMM2-generated structures into a coarse-grained representation, thus allowing larger time and length scales to be explored. By employing a conformer search technique, direct construction and analysis of coarse-grained SOM models with diverse compositions were made possible, eliminating the need for atomistic MD simulations. To demonstrate this approach, coarse-grained SOM models were created based on selected samples from the International Humic Substances Society, considering different water content levels for each model. Comprehensive analyses, including density and potential energy profile calculations, revealed a partial correlation with the SOM compositions and demonstrated that electrostatic interactions govern the structural packing. Moreover, a local phase separation process, particularly the formation of SOM voids, was observed over several microseconds, underscoring the advantages of the coarse-graining technique.

Inion Sulfocation Membranes Plasticized with Propylene Carbonate

The rapidly developing field of portable energy sources requires the search and development of effective materials for such devices. To improve the safety of the most common metal-ion batteries (lithium- and sodium-ion), instead of a liquid electrolyte, it is proposed to use a gel-polymer electrolyte with unipolar conductivity based on a Nafion-like electrolyte (Inion), plasticized with aprotic solvents. The work presents the results of a study of the thermal stability, molecular structure and supramolecular packing, as well as ionic conductivity of the Inion membrane in lithium and sodium forms, plasticized with propylene carbonate, using methods of simultaneous thermal analysis, IR spectroscopy, small-angle X-ray scattering and impedance spectroscopy.

Exploring disordered packing of non-equant particles: Insights from computed tomography and Monte Carlo simulations

The influence of particle shape on disordered packing structures is investigated through a combined experimental and modeling approach, focusing on non-equant particles, i.e. particles which are either elongated or flat, or both. In an experimental campaign, particles of systematically chosen shapes are fabricated via 3D printing, then packed and imaged by X-ray Computed Tomography to extract packing properties such as the porosity, particle orientations, and tortuosities of paths through the pore space. Additionally, a Monte Carlo model is employed to simulate packing structures, allowing for broader exploration of the parameter space, and investigating properties which are challenging to measure experimentally. The model’s parameters are varied to probe the range of potential packing structures for various particle shapes, and to provide explanations for experimental results. Both model and experiments reveal a non-monotonic trend for the porosity, a monotonically decreasing trend for the average particle inclination, and a monotonically increasing trend for the tortuosity with respect to elongation and flatness. Additionally, both model and experiments show increased dependence of the packing properties on the packing method (pouring or shaking), or model parameters respectively as particle aspect ratio increases. Furthermore, the model can predict experimentally measured packing porosities with deviations of 0.03 in absolute porosity units at most for new particle shapes, once its parameters are fitted to match the physical context. This research provides insights into the effect of particle shape on packing structure, with practical implications to processes involving the packing of non-equant particles, such as crystal filtration and packed beds.

Synthesis, structure, thermal, spectroscopic and theoretical investigations on novel nonlinear metal-organic hexa-aqua magnesium creatinium sulphate single crystal

A novel Hexa-aqua magnesium creatinium sulphate (HMCS) material was synthesized and grown using slow evaporation method and the crystal is monoclinic with centrosymmetric space group P21/n. Optimized molecular geometry inferred that the overall structure of HMCS comprises a hydrogen bonded network. The optical activity of the grown crystal has been examined by using UV–visible spectral analysis. The most abundant O⋯H interaction (49.5 %) in HMCS influences the stabilization of the packing in the crystal structure. The HOMO LUMO plot was used to determine the molecule's chemical potential, electro-negativity, and chemical hardness. The emission behaviour of HMCS single crystal has been examined by using fluorescence spectral analysis. Thermal stability of the synthesized single crystal was analysed by using TG/DTA analysis. Thirdorder nonlinear optical (NLO) behaviour of HMCS compound was illuminated by the Z-scan method.

A Helical Tubular Dyad of [9]Cycloparaphenylene: Synthesis, Chiroptical Properties and Post-functionalization.

The bottom-up synthesis of discrete tubular molecules that mimic the structural features of carbon nanotubes has been a long-standing pursuit for synthetic chemists. As the shortest segments of armchair-type carbon nanotubes, cycloparaphenylenes are regarded as ideal macrocyclic building blocks for achieving this goal. Here we report the synthesis of a helical tubular molecule featuring three diyne linkers between two site-specifically functionalized [9]cycloparaphenylene. Its C3-symmetrical, radially conjugated structure and solid-state packing have been elucidated by spectroscopic and crystallographic characterizations. Notably, the resolved enantiomers display a circularly polarized luminescence brightness value of 1.47 × 103 M-1 cm-1, which is among the highest values for chiral organic molecules. Furthermore, the diyne-linked molecule could be directly converted into a thiophene-linked helical molecule, demonstrating the post-functionalization approach for the construction of chiral tubular molecules from cycloparaphenylenes.

Synthesis, Structures, and Physical Properties of ExTTF Substituted with Aryl Groups Through Sulfur Bridges and the Electron Transfers with C60

ExTTF derivatixes (1‐4) bearing aryl groups attached through sulfur bridges have been synthesized. The peripheral aryl groups have a certain influence on both the electronic and crystallographic properties of the exTTFs. Compounds 1‐4 show two bands typical of exTTF derivatives near 360 and 430 nm. Compound 1 and 4 exhibit the characteristic electrochemical exTTF behavior, with one reversible two‐electron process ranging depending on their substitutionthe electron‐withdrawing ability. But 2 and 3 exhibit a similar single two‐electron oxidation wave but electrochemically irreversible redox with peak‐to‐peak potential separation. And 3 has a low redox potential, which is significantly inconsistent with the electron absorption of pyridine substituents. The crystal structures of 1‐4 exhibit the characteristic butterfly shape. Moreover, the peripheral aryl groups exhibit multiple alignment modes with respect to the central exTTF core, caused by their rotation about the two C‐S bonds of the sulfur bridges. Under the interaction of multiple molecules, exTTF shows different molecular packing structures. Compounds 1‐4 have good intermolecular interaction with C60 due to their good electron‐donating ability, butterfly configuration, and free rotation of peripheral aryl groups. These results indicate that 1‐4 organic electronic materials have potential applications in the field of supramolecular assembly.

Morphology- and crystal packing-dependent singlet fission and photodegradation in functionalized tetracene crystals and films.

Singlet fission (SF) is a charge carrier multiplication process that has potential for improving the performance of (opto)electronic devices from the conversion of one singlet exciton S1 into two triplet excitons T1 via a spin-entangled triplet pair state 1(TT). This process depends highly on molecular packing and morphology, both for the generation and dissociation of 1(TT) states. Many benchmark SF materials, such as acenes, are also prone to photodegradation reactions, such as endoperoxide (EPO) formation and photodimerization, which inhibit realization of SF devices. In this paper, we compare functionalized tetracenes R-Tc with two packing motifs: "slip-stack" packing in R = TES, TMS, and tBu and "gamma" packing in R = TBDMS to determine the effects of morphology on SF as well as on photodegradation using a combination of temperature and magnetic field dependent spectroscopy, kinetic modeling, and time-dependent density functional theory. We find that both "slip-stack" and "gamma" packing support SF with high T1 yield at room temperature (up to 191% and 181%, respectively), but "slip-stack" is considerably more advantageous at low temperatures (<150K). In addition, each packing structure has a distinct emissive relaxation pathway competitive to SF, while the states involved in the SF itself are dark. The "gamma" packing has superior photostability, both in regards to EPO formation and photodimerization. The results indicate that the trade-off between SF efficiency and photostability can be overcome with material design, emphasize the importance of considering both photophysical and photochemical properties, and inform efforts to develop optimal SF materials for (opto)electronic applications.

A Double-walled Noncovalent Carbon Nanotube by Columnar Packing of Nanotube Fragments.

Herein, we report the synthesis of double-walled noncovalent carbon nanotubes (CNTs) through host-guest complexation of nanotube fragments and tube-forming crystal engineering. As the smallest fragment of double-walled CNTs, a host-guest complex of perfluorocycloparaphenylene (PFCPP) and carbon nanobelt (CNB) was synthesized by mixing them in solvents. The immediate complexation of the PF[12]CPP⸧(6,6)CNB complex with a remarkably high association constant (Ka) of 2×105 L/mol was observed. Time-dependent 1H NMR and thermogravimetry measurements revealed that the stability of (6,6)CNB was significantly improved by encapsulation. X-ray crystallography confirmed the robust belt-in-ring structure of this complex. As indicated by the short distance between PF[12]CPP and (6,6)CNB (2.8 Å), intermolecular orbital interactions exist between the belt and the ring, which were further supported by theoretical calculation and phosphorescence quenching experiments. While the PF[12]CPP⸧(6,6)CNB complex adopts various crystal packing structures, chloroform was discovered to be a magic "glue" solvent inducing one-dimensional alignment of the PF[12]CPP⸧(6,6)CNB complex to build an unprecedented double-walled noncovalent CNT structure.

A Double‐walled Noncovalent Carbon Nanotube by Columnar Packing of Nanotube Fragments

AbstractHerein, we report the synthesis of double‐walled noncovalent carbon nanotubes (CNTs) through host–guest complexation of nanotube fragments and tube‐forming crystal engineering. As the smallest fragment of double‐walled CNTs, a host–guest complex of perfluorocycloparaphenylene (PFCPP) and carbon nanobelt (CNB) was synthesized by mixing them in solvents. The immediate complexation of the PF[12]CPP⸧(6,6)CNB complex with a remarkably high association constant (Ka) of 2×105 L/mol was observed. Time‐dependent 1H NMR and thermogravimetry measurements revealed that the stability of (6,6)CNB was significantly improved by encapsulation. X‐ray crystallography confirmed the robust belt‐in‐ring structure of this complex. As indicated by the short distance between PF[12]CPP and (6,6)CNB (2.8 Å), intermolecular orbital interactions exist between the belt and the ring, which were further supported by theoretical calculation and phosphorescence quenching experiments. While the PF[12]CPP⸧(6,6)CNB complex adopts various crystal packing structures, chloroform was discovered to be a magic “glue” solvent inducing one‐dimensional alignment of the PF[12]CPP⸧(6,6)CNB complex to build an unprecedented double‐walled noncovalent CNT structure.

Substitution effect and charge transport properties in organic field-effect transistors (OFETs) of simply functionalized carbazole derivatives

Development of low cost, easy-preparation and good performance organic semiconductors is in high demand for the practical application of organic field-effect transistors (OFETs). Even though the π-extended carbazole derivatives have been intensively studied in OFETs, the application potential of simple carbazole derivatives, i.e., owning simple substituents directly at carbazole backbone, remains unclear. In this work, we designed and synthesized a series of carbazole derivatives with simple phenyl or thienyl functionalization directly at 2,7- or 2,6-positions, respectively. The photophysical and electrochemical properties, together with their theoretical frontier molecular orbitals and energy levels were investigated. The molecular conformations and packing structures in the solid state of these molecules were understood by single-crystal structure analysis. In addition, single-crystal based OFETs were fabricated to explore their intrinsic charge transporting properties, in which the 2,7-diphenyl modified carbazole derivative showed hole-transporting mobilities up to 0.16 cm2 V−1 s−1. Our study not only proves that simply functionalized carbazoles have great potentials to act as easy-preparation high-performance p-type semiconducting materials, but also illustrates that 2,7-positon functionalization is more advantageous for balancing the molecular conformations and packing structures of carbazole derivatives to achieve good charge transport performance.

Effects of the inclusion shape, arrangement, and volume fraction on effective elastic moduli of two-dimensional two-phase composites

The spatial arrangement and shape of inclusions can have a major impact on two-phase composites' mechanical properties. Few studies consider the coupling effects of these two factors on the effective elastic moduli of two-phase composites. This study introduces the circularity of inclusions to modify the three-point approximation (TPA) for quantitatively predicting the coupling effects of inclusion planar arrangement and shape. Two-dimensional particle packing structures of monosized particles are generated with polygons, superellipses, and superovals of different circularities and volume fractions via the ordered arrangement approach or the discrete element method. Then, the lattice model is conducted on the particle packing structures to verify the reliability of the modified TPA. The comparison between the theoretical calculation and the numerical simulation indicates that our modified TPA can predict the effects of planar arrangement, shape, and volume fraction of inclusions on the effective moduli. The proposed modified TPA offers fresh perspectives on comprehending intricate relationships between the macro-property and composition of composites.

Optimizing Exciton Diffusion and Carrier Transport for Enhanced Efficiency in Q‐PHJ and BHJ Organic Solar Cells

AbstractExciton diffusion and carrier transport are two critical factors that determine the efficiency of organic photovoltaics (OPVs). However, the relationship between these two factors has not been extensively studied. Designing non‐fullerene acceptors (NFAs) with efficient diffusion coefficients and high electronic transmittance is a key area of focus. In this study, materials for bulk‐heterojunction (BHJ) and quasiplanar‐heterojunction (Q‐PHJ) devices are synthesized to validate the desired differences in crystallinity. The single crystal of BOBO4Cl‐βδ demonstrated the most compact packing structure, with an improved planar configuration and closer π···π distances, resulting in higher electron mobility and superior exciton diffusion coefficient. Consequently, BOBO4Cl‐βδ‐based devices achieved a power conversion efficiency (PCE) of 17.38% in Q‐PHJ, compared to a lower PCE of 14.75% in BHJ devices. Furthermore, incorporating BOBO4Cl‐βδ into the D18/L8‐BO Q‐PHJ system increased the PCE from 17.98% to 18.81%, one of the highest values recorded for Q‐PHJ devices. This improvement is attributed to strong crystallinity of BOBO4Cl‐βδ, which enhances the packing arrangement and improves the exciton diffusion coefficient. Our work highlights the importance of molecular design with tunable exciton diffusion and carrier transport for BHJ and Q‐PHJ OPV architectures and reveals the relationship between them, which contributes to the achievement of high‐performance NFAs.

Increased thermal stability and catalytic efficiency of 3-ketosteroid Δ1-dehydrogenase5 from Arthrobacter simplex significantly reduces enzyme dosage in prednisone acetate biosynthesis

The 3-ketosteroid-Δ1-dehydrogenase5 (KsdD5) from Arthrobacter simplex converts cortisone acetate to prednisone acetate, an important step in steroid catabolism. To achieve sustainable and efficient enzyme production, we employed computer-aided screening, structural analysis, and combinatorial experiments to identify engineered KsdD5 variants (M1 and M3) with dual advantages of stability and active sites. M1 had a 8.2-fold longer half-life (19.6 h at 30 °C) than KsdD5-WT, an 11.8 °C higher half-inactivation temperature (T5015min), and a 10.6 °C higher melting temperature (Tm). M3 had 3.82-fold higher catalytic activity than WT, a 3.9-fold longer half-life at 30 °C, and higher T5015min and Tm by 14 °C and 6.9 °C, respectively. Furthermore, kinetic and microscale thermophoresis analyses revealed M3 exhibited higher catalytic efficiency due to its larger enzymatic channel. Molecular dynamics simulations showed M1 promoted tighter secondary structure packing, reduced residue flexibility, and increased hydrogen bond formation, ensuring enzyme stability and activity at elevated temperatures. Under industrial conditions, M1 converted >96 % cortisone acetate within 12 h at 30 °C with a 60 g·L−1 substrate dosage and 6 g·L−1 cell mass, whereas the M3 conversion rate was 95 %. This study demonstrates a robust strategy for developing efficient enzyme mutants, facilitating sustainable industrial production of prednisone acetate with a minimal enzyme dosage.

NMR residual dipolar couplings investigation in the topology of house dust mite Group V allergens

Blo t 5 is an important major allergen protein from Blomia tropicalis mites, which are prevalent in tropical and subtropical regions, including Taiwan. It is a coiled-coil triple helical bundle, but there currently is ambiguity around its structural fold and packing of the three helices. We have relied on NMR residual dipolar coupling data collected from four different alignment media to confirm that Blo t 5 has left-handed helical topology and further used that data to refine its solution structure. Earlier we had described conformational epitope for a detection monoclonal antibody by exclusive use of TROSY NMR experiments that studied Blo t 5 binding with the antibody FAB’ fragment. Here, we confirm those findings with an extensive mutagenesis and biophysical study to validate the NMR epitope mapping approach proposed by us.

Nitrogen-Bridged Fused-Ring Nonacyclic and Heptacyclic A-D-A Acceptors for Organic Photovoltaics.

In this work, we designed two nitrogen-bridged fluorene-based heptacyclic FNT and nonacyclic FNTT ladder-type structures, which were constructed by one-pot palladium-catalyzed Buchwald-Hartwig amination. FNT and FNTT were further end-capped by FIC acceptors to form two FNT-FIC and FNTT-FIC non-fullerene acceptors (NFAs), respectively. The two NFAs exhibit more red-shifted absorption and higher crystallinity compared to those of the corresponding carbon-bridged FCT-FIC and FCTT-FIC counterparts. Grazing incidence wide-angle X-ray scattering (GIWAXS) measurements reveal that the 2-butyloctyl groups on the nitrogen in the convex region of FNT-FIC interdigitate with the dioctyl groups on the fluorene in the concave region of another FNT-FIC, resulting in a lamellar packing structure with a d spacing of 13.27 Å. As a consequence, the PM6:FNT-FIC (1:1 wt %) device achieved a power conversion efficiency (PCE) of only 6.60%, primarily due to the highly crystalline nature of FNT-FIC, which induced significant phase separation between PM6 and FNT-FIC in the blended film. However, FNTT-FIC, featuring 2-butyloctyl groups positioned on the nitrogen within the concave region of its curved skeleton, exhibits improved donor-acceptor miscibility, thereby promoting a more favorable morphology. As a result, the PM6:FNTT-FIC (1:1.2 wt %) device exhibited a higher PCE of 12.15% with an exceptional Voc of 0.96 V. This research demonstrates that placing alkylamino moieties within the concave region of curved A-D-A NFAs leads to a better molecular design.

Synthesis, structural studies and Hirshfeld surface analysis of the substituted isoindole-1,3‑dione derivatives

In this study, we have performed the ring-opening reaction of 5-benzyl/ethyl-2-hydroxyhexahydro-4H-oxireno[2,3-e] isoindole-4,6(5H)‑dione (10) with HBr to the corresponding bromodiols, regioselectively. Structures of the synthesized compounds are elucidated through spectral methods (1H NMR,13C NMR and HRMS) Afterwards, the racemic products 11a-b were purified and the absolute geometries of 5‑bromo-2-ethyl-4,6-dihydroxyhexahydro-1H-isoindole 1,3(2H)‑dione (11a) and 2-benzyl-5‑bromo-4,6-dihydroxyhexahydro-1H-isoindole-1,3(2H)‑dione (11b) was determined by X-ray diffraction analysis. Effective O−H∙∙∙O (2.738–2.874 Å) hydrogen bonds between diol and ketone units are important interactions between the molecules. Hirshfeld surface analyses of the compounds (11a-b) have provided further insights into molecular, crystal structure and intermolecular interactions. The results indicated that the most important contributions for the crystal packings are from H∙∙∙H, O∙∙∙H/H∙∙∙O, C∙∙∙H/H∙∙∙C and Br∙∙∙H/H∙∙∙Br interactions. Finally, energy frameworks were analyzed to a better understanding of the packing of crystal structure and the supramolecular rearrangements for the structures (11a-b).

Effect of Halogen Substituents on Charge Transport Properties of n-type Organic Semiconductors: A Theoretical Study.

Organic semiconductors (OSCs) have received significant attention as promising materials for electronic devices. In this study, we investigate the impact of halogen groups on the charge transport properties of n-type OSC-6,13 bis((triisopropylsilyl)ethynyl)-5,7,12,14-tetraazapentacene (TIPS-TAP). The computed mobilities for TIPS-TAPs substituted with F and Cl exhibit excellent agreement with the experimental values, while the simulation overestimates the electron mobility for TIPS-TAP. Interestingly, the mobility of TIPS-TAP-4F is significantly lower than that of TIPS-TAP-4Cl/Br, despite their similar packing structures. This discrepancy can be attributed to the strong electron-withdrawing effect of fluoride, which reduces the electron transfer integral and increases the reorganization energy. While molecular packing is widely recognized as a dominant factor in charge transport in OSCs, our study highlights the crucial role of electronic effects in charge transport in OSCs. This study provides new insights into the mechanisms underlying charge transport in OSCs.

Premelting Theory‐Based Mechanism for Water Freezing in Saline Soil

AbstractThe unfrozen water content constitutes a pivotal parameter in freezing soil, significantly impacting its thermal‐mechanical and deformation behavior. This study delves into the alterations in soil attributes as unfrozen water content varies. It examines the influences of impurities, van der Waals forces, and Coulomb forces on the water film, employing the premelting theory as a foundation. A critical state curve quantifying the ratio of the surface charge density to impurity concentration is parameterized for various soil types. Subsequently, combining the theory of effective solution concentration, we have provided calculation methods for the particle surface parameters of pore solutions as ideal and non‐ideal dilute solutions, respectively. This has determined the key variables in the model. Additionally, through the integration of equivalent particle sizes, packing structure, and water film thickness, a calculation model is devised and verified for determining the unfrozen water content and residual water content within in freezing soil. The findings indicate that fluctuation in the unfrozen water content primarily stem from impurities. In soils with equivalent saline content, impurity levels exhibit proportionality to the equivalent particle sizes. The residual unfrozen water is predominantly present within the absorbed water layer.

Structure and function of skin barrier lipids: Effects of hydration and natural moisturizers in vitro

Lipid membranes play a crucial role in regulating the body’s water balance by adjusting their properties in response to hydration. The intercellular lipid matrix of the stratum corneum (SC), the outermost skin layer, serves as the body’s primary defense against environmental factors. Osmolytes, including urocanic acid (UCA) and glycerol, are key components of the natural moisturizing factor that help the SC resist osmotic stress from dry environments. This study examines the effects of UCA and glycerol (each at 5 mol %) on isolated human SC lipids. For this, different techniques were employed, offering complementary information of the system’s multiscale characteristics, including humidity-scanning quartz crystal microbalance with dissipation monitoring, infrared spectroscopy, x-ray diffraction, electrical impedance spectroscopy, and studies of water loss and permeability. Our results show that UCA increases water sorption and makes lipid films more liquid-like at high relative humidity, without significantly altering the lipid lamellar structure, chain order, or orthorhombic chain packing. Lipid films containing UCA exhibited higher water loss and significantly higher model drug permeability compared to lipid films without UCA. Further, incorporation of UCA resulted in kinetically faster changes in electrical properties upon contact with aqueous solution compared with control lipids. These observations suggest that UCA reduces lipid cohesion in regions other than the acyl chain-rich leaflets, which may impact SC desquamation. In contrast, glycerol did not influence the hydration or permeability of the SC lipid matrix. However, it increased the proportion of orthorhombic domains at high humidities and slowed the kinetics of the hydration process, as evidenced by slower changes in the dielectric properties of the lipid film. These findings suggest that glycerol enhances lipid cohesion rather than increasing water uptake, which is typically the expected function of humectants. Consequently, UCA and glycerol appear to have distinct roles in maintaining epidermal homeostasis.

INVESTIGATION OF RARE AND RARE-EARTH ELEMENTS LEACHING PROCESSES FROM THE WEATHERING CRUST ORES OF THE KUNDYBAY DEPOSIT

The weathering crust ore of the Kundybay deposit is a hard-enriched ore that contains such minerals as cherchite, bastnesite, kaolinite, etc., which are embedded in the matrix structure of other silicate rocks. These minerals contain rare earth (RE) and rare earth elements (REE). The multi-component structure and dense packing of minerals in the aluminosilicate matrix of the ore make it difficult to be blocking out. Determination of the optimal ore blocking method in order to extract RE and REE is an urgent task for today. The purpose of this work is to develop an effective method of leaching RE, REE and "white soot" from the weathering crust ores of the Kundybay deposit. Methods. Processing with soluble ammonium, magnesium and aluminium salts will allow estimation of the state of RE and REE in the ore. The indicator of RE and REE blocking out during leaching with sodium hydroxide is the transfer of silica into solution, due to which RE and REE form their own hydroxides, which can be subsequently transferred into solution by acid treatment. Acid leaching with sodium pyrosulfite, hydrofluoric acid and sulfuric acid will allow the RE and REE to be immediately transferred into solution. Results and Discussion. The main characteristics of the Kundybay deposit weathering crust ore were determined, such as: silica content, moisture content, base metals, RE and REE. Conclusion. The degree of extraction of RE and REE by soluble salts of ammonium, magnesium and aluminium did not exceed 2%, which indicates the existence of RE and REE in the form of their own minerals. Leaching with sodium hydroxide showed low recovery of silica, with RE and REE remaining in a difficult-torecover form. Leaching with a mixture of sodium pyrosulfite, hydrofluoric and sulfuric acids is a promising method for RE and REE recovery due to the complex effect of the components of this mixture.