Solid State Sciences最新文献

{"title":"Fe-doping effect on CoMoO4 for electrochemical oxygen evolution in neutral media","authors":"Li Yu,&nbsp;Qin Liang","doi":"10.1016/j.solidstatesciences.2025.108078","DOIUrl":"10.1016/j.solidstatesciences.2025.108078","url":null,"abstract":"<div><div>As an economically viable and environmentally benign electrocatalyst, CoMoO₄ has emerged as a promising alternative to noble metal-based water oxidation catalysts in recent years. However, the oxygen evolution reaction (OER) under neutral condition presents a significantly greater challenge compared to reactions occurring in acidic or alkaline electrolytes. Therefore, to further enhance the OER activity of CoMoO₄ under neutral conditions, we adopted an Fe-doping strategy. By precisely controlling the synthesis time, we successfully developed a series of Fe-CoMoO-X samples with varying morphologies (where X represents the synthesis time, ranging from 10 to 16 h) for electrocatalytic OER. By integrating multiple material characterization techniques with advanced electrochemical evaluation methods, we confirmed that the synthesis time profoundly influences the morphology of the Fe-CoMoO-X samples, which directly correlates with their catalytic performance for oxygen evolution. Moreover, all Fe-doped samples demonstrate markedly enhanced electrocatalytic activity compared to pristine CoMoO₄. Notably, the Fe-CoMoO-13 h sample exhibits the most superior oxygen evolution performance, achieving an overpotential of only 380 mV at a 10 mA cm⁻² (Tafel slope of 289 mV dec⁻¹), substantially lower than that of pure CoMoO₄ (400 mV at 10 mA cm⁻²; Tafel slope of 403 mV dec⁻¹). This improvement can be attributed to the partial substitution of Co atoms with Fe atoms in the doped CoMoO₄ structure, which modulates its electronic properties and enhances charge transfer kinetics.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108078"},"PeriodicalIF":3.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eco-friendly synthesis of coal tar-derived oxygen-rich porous carbons for ultra-long-life zinc-ion hybrid supercapacitors","authors":"Yuxiao Zhu ,&nbsp;De Yang ,&nbsp;Haoran Liu ,&nbsp;Yuanchun Zhang ,&nbsp;Ting Zhu ,&nbsp;Feng Wei ,&nbsp;Yaohui Lv","doi":"10.1016/j.solidstatesciences.2025.108072","DOIUrl":"10.1016/j.solidstatesciences.2025.108072","url":null,"abstract":"<div><div>Zinc-ion hybrid supercapacitors (ZHSs) have emerged as a promising energy storage technology, combining the high energy density of batteries with the superior power density and cycling stability of supercapacitors. Nevertheless, the development of high-performance electrode materials for ZHSs remains a significant challenge. Herein, we report an environmentally friendly synthesis of oxygen-doped hierarchical porous carbons derived from coal tar, using calcium gluconate as a multifunctional template and K₂CO₃ as a mild activating agent. The optimized carbon cathode (MCK) possesses a high specific surface area up to 1067.6 m² g⁻¹ and an appropriate oxygen doping content of 6.05 at%, which collectively provide abundant active sites for Zn²⁺ storage and facilitate efficient ion transport pathways. As a result, the MCK cathode delivers a high specific capacity of 181.8 mAh g⁻¹ at 0.05 A g⁻¹, outperforming most previously reported carbon-based cathodes. Furthermore, it achieves impressive energy and power densities of 145.1 Wh kg⁻¹ and 13.9 kW kg⁻¹, respectively, along with exceptional cycling stability with 92.98 % capacity retention after 100,000 cycles. This work not only offers valuable insights into carbon material design but also demonstrates a scalable and green synthesis strategy for advanced energy storage applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108072"},"PeriodicalIF":3.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration and control of short-chain spacer cations propylammonium and propanediammonium for tuning structure property performance relationships in 2D perovskites","authors":"Aboubacar Traore ,&nbsp;Mohammadreza Hosseini ,&nbsp;Atena Pakzadiyan ,&nbsp;Xing Li ,&nbsp;Jiahong Pan ,&nbsp;Xuepeng Liu ,&nbsp;Songyuan Dai ,&nbsp;Molang Cai","doi":"10.1016/j.solidstatesciences.2025.108073","DOIUrl":"10.1016/j.solidstatesciences.2025.108073","url":null,"abstract":"<div><div>The structural diversity of 2D perovskites, resulting from the integration of various spacer cations, remains insufficiently explored, necessitating a thorough investigation into the mechanisms that govern their structural, optoelectronic, surface moisture resistance, mechanical stability, and photovoltaic performance. This study examines the use of short-chain spacer cations to adjust and control these properties. We analyse the impact of Propylammonium (PA⁺) and Propanediammonium (PDA²⁺) on the structure-property-performance relationships in Ruddlesden-Popper-type (PA₂(MA)Pb₂I₇) and Dion-Jacobson-type (PDA(MA)Pb₂I₇) perovskites, based on first-principles calculations. Our results demonstrate that incorporating PDA²⁺ yields shorter intercalation distances, a higher volumetric density (3.87 g/cm³), and a more compact structure, resulting in monoclinic symmetry and a narrower band gap (1.8 eV). This configuration enhances absorption and charge carrier transport by lowering the excitation binding energy, resulting in a more pronounced Rashba effect due to reduced symmetry. This, in turn, enhances carrier lifetime through indirect transitions. These factors contribute to a higher short-circuit current density (19.64 mA/cm²) and better SLME efficiency (27 %) compared to that of PA₂(MA)Pb₂I₇ (11.16 mA/cm², 19 %), which adopts a less compact orthorhombic structure (3.17 g/cm³) with a wider band gap (2.17 eV). Mechanical analysis reveals that both perovskites are ductile, with the PDA²⁺-based perovskite showing greater rigidity and fracture resistance. In contrast, the PA⁺ cation induces higher ductility, as well as a higher water migration barrier and better resistance to water absorption compared to the PDA²⁺ cation. These results highlight the crucial importance of spacer cation selection and crystalline symmetry in determining the properties of 2D perovskites.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108073"},"PeriodicalIF":3.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"P-type thermoelectric properties of TiNi1–x–yCoySn half-Heusler alloy with reduced interstitial Ni atoms","authors":"Kosuke Yamazaki ,&nbsp;Sopheap Sam ,&nbsp;Hiroshi Nakatsugawa","doi":"10.1016/j.solidstatesciences.2025.108060","DOIUrl":"10.1016/j.solidstatesciences.2025.108060","url":null,"abstract":"<div><div>TiNiSn is an N-type thermoelectric material with low toxicity. The electrical conduction of TiNiSn can be tuned from N-type to P-type by substituting Co atoms at Ni sites. However, the <em>ZT</em> value is lower than that of the N-type TiNiSn, primarily due to its higher electrical resistivity. To decrease the electrical resistivity, it is necessary to increase the carrier density or mobility; however, the absolute value of the Seebeck coefficient decreases, which has a trade-off relationship with the electrical resistivity. To solve this problem, we prepared P-type thermoelectric materials TiNi_{1<strong>–</strong><em>x</em><strong>–</strong><em>y</em>}Co_<em>y</em>Sn (0 ≤ <em>x</em> ≤ 0.1, 0.01 ≤ <em>y</em> ≤ 0.05) with reduced interstitial Ni atoms by arc melting and heat treatment process. As a result, we successfully improved the electrical conductivity while maintaining the Seebeck coefficient. The hole carrier density increases as the number of interstitial Ni atoms decreases, and the electrical resistivity decreases by 78 % from 2.78 × 10⁻² Ωcm (for <em>x</em> = 0, <em>y</em> = 0.05) to 6.02 × 10⁻³ Ωcm (for <em>x</em> = 0.03, <em>y</em> = 0.05) at 300 K. The <em>ZT</em> value increases by a factor of 1.5 (<em>ZT</em>_max = 0.18 at 700 K) for TiNi_0.92Co_0.05Sn compared to TiNi_0.95Co_0.05Sn, indicating that the reduction of interstitial Ni atoms is effective in improving the thermoelectric properties of the P-type half-Heusler alloy TiNiSn. The peak <em>ZT</em> of 0.18 remains below the level required for practical implementation; however, this can be further improved by decreasing the lattice thermal conductivity.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108060"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New layered quaternary Zintl pnictide oxides Ba2Zn2Pn2O (Pn = Sb, Bi): Discovery, crystal structures, band engineering, and transport properties","authors":"Mohd Ishtiyak ,&nbsp;Hussien H. Osman ,&nbsp;Spencer R. Watts ,&nbsp;Md Rashed Alam ,&nbsp;S.M. Gayomi K. Samarakoon ,&nbsp;Thimira Kandabadage ,&nbsp;Bhushan Thipe ,&nbsp;Samuel Gallego-Parra ,&nbsp;Xiaojian Bai ,&nbsp;David P. Young ,&nbsp;Sviatoslav Baranets","doi":"10.1016/j.solidstatesciences.2025.108059","DOIUrl":"10.1016/j.solidstatesciences.2025.108059","url":null,"abstract":"<div><div>Three new heteroanionic oxypnictides, Ba₂Zn₂Sb₂O, Ba₂Zn₂Bi₂O, and the solid solution Ba₂Zn₂Sb_{2−<em>x</em>}Bi_<em>x</em>O (<em>x</em> ≈ 1.1–1.6), have been synthesized and structurally characterized. They are isostructural with their Mn-bearing analog, adopting the Ba₂Mn₂Sb₂O-type structure (space group <em>P</em>6₃/<em>mmc</em>, No. 194), and feature a double-layered 2D <span><math><mrow><mtable><mtr><mtd><mn>2</mn></mtd></mtr><mtr><mtd><mi>∞</mi></mtd></mtr></mtable></mrow></math></span> [Zn₂<em>Pn</em>₂O]^2- substructure (<em>Pn</em> = Sb, Bi, Sb/Bi) composed of corner-sharing, distorted tetrahedral Zn<em>Pn</em>₃O units. Electronic structure calculations reveal a systematic progression from semiconducting Ba₂Zn₂Sb₂O to metallic Ba₂Zn₂Bi₂O as Bi content increases. These trends are corroborated by transport property measurements, with Ba₂Zn₂Sb_0.9(1)Bi_1.1O exhibiting relatively low electrical resistivity, high Hall mobilities of ∼160 cm²/V·s, and large Seebeck coefficients from 69 to 132 μV K⁻¹ over the 300–600 K temperature range. Comparison with structurally related Zintl pnictides, such as SrIn₂As₂ and PrZn₃As₃ phases, situates Ba₂Zn₂<em>Pn</em>₂O (<em>Pn</em> = Sb, Bi) within a broader family of heteroanionic oxypnictide Zintl compounds, highlighting their structural flexibility and amenability to band engineering. Electronic structure and bonding considerations point to tunable semiconducting behavior and underscore the relevance of these materials for thermoelectric and topological applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108059"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating mechanical properties of WAlB MAB phase synthesized via spark plasma sintering","authors":"Burak Demir","doi":"10.1016/j.solidstatesciences.2025.108071","DOIUrl":"10.1016/j.solidstatesciences.2025.108071","url":null,"abstract":"<div><div>This study investigates the synthesis and characterization of WAlB ceramics produced via spark plasma sintering (SPS). High-purity tungsten (W), aluminum (Al), and boron (B) powders were mixed and subjected to SPS at 700 °C under a constant pressure of 30 MPa for different dwell times. The phase composition and microstructural evolution of the sintered samples were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results indicate that WAlB forms as the primary phase, with residual metallic W diminishing as the dwell time increases. SEM analysis reveals a reduction in porosity and an increase in densification with prolonged dwell times, which supports the phase transformation observed in the XRD patterns. Hardness measurements indicate that the obtained WAlB ceramics exhibit lower hardness values than those reported for single-crystal WAlB, which is attributed to incomplete densification and residual metallic W. The formation of cracks around indentation marks suggests brittleness and structural heterogeneity. The findings highlight the influence of sintering parameters on phase evolution and mechanical properties, providing insights into optimizing the synthesis of WAlB ceramics.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108071"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hierarchical organic-inorganic PANI/CuWO4 nanocomposite as high-performance and robust electrode for advanced supercapacitors","authors":"Ali B.M. Ali ,&nbsp;Syed Waheedullah Ghori ,&nbsp;M.A. Diab ,&nbsp;Rekha M M ,&nbsp;Subhashree Ray ,&nbsp;Kattela Chennakesavulu ,&nbsp;Renu Sharma ,&nbsp;Asilbek Abdullaev ,&nbsp;Mutabar Latipova ,&nbsp;Ruslanbek Siddikov ,&nbsp;Aseel Smerat","doi":"10.1016/j.solidstatesciences.2025.108070","DOIUrl":"10.1016/j.solidstatesciences.2025.108070","url":null,"abstract":"<div><div>The development of advanced supercapacitor electrode materials with high energy density and robust cycling stability remains a critical challenge for next-generation energy storage systems. Hybrid nanocomposites combining conductive polymers and transition metal oxides offer a promising route to overcome these limitations by integrating the merits of both components. In this study, a polyaniline (PANI)/CuWO₄ nanocomposite was synthesized through in situ oxidative polymerization of aniline in the presence of CuWO₄ nanoparticles, and the resulting material was directly deposited onto a nickel sheet (NS) substrate using a drop-casting method without the addition of binders. The structural and morphological properties of the composite were characterized using FESEM, TEM, XRD, XPS, and EDS analyses, which collectively revealed a hierarchical flower-like nanosheet architecture for the PANI/CuWO₄ nanocomposite. Electrochemical performance was evaluated in a two-electrode configuration with 6 M KOH electrolyte via cyclic voltammetry and galvanostatic charge–discharge (GCD) measurements. The PANI/CuWO₄/NS electrode exhibited an outstanding specific capacitance of 323 F g⁻¹ at 0.5 A g⁻¹, a high energy density of 16.16 Wh kg⁻¹, and excellent capacitance retention of 90.75 % after extensive cycling. The hierarchical porous architecture, confirmed by BET and TEM, facilitated rapid ion/electron transport and buffered mechanical stress during repeated charge/discharge cycles. These results highlight the PANI/CuWO₄/NS nanocomposite as a highly efficient and durable electrode material for advanced supercapacitor applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108070"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pore-partitioned bimetallic metal-organic frameworks for efficient photocatalytic activation of peroxymonosulfate","authors":"Wenxu Ma,&nbsp;Zhiyong Liu,&nbsp;Yunqiong Yang","doi":"10.1016/j.solidstatesciences.2025.108056","DOIUrl":"10.1016/j.solidstatesciences.2025.108056","url":null,"abstract":"<div><div>Metal-organic frameworks (MOFs) have been widely explored in photocatalytic peroxymonosulfate-based (PMS) advanced oxidation processes (AOPs) due to their highly tunable and porosity structures. In this work, three pore-partitioned MOF materials, namely [Fe₃M₂O(BDC)₃(trz)₃Cl₂(H₂O)₄]·solvent (Fe₃+M₂, M = Mg, Fe, or Zn, BDC = terephthalic acid, trz = 1,2,4-triazole), were successfully synthesized by embedding binuclear units [M₂(trz)₃] (M = Mg, Fe, or Zn) into a MIL-88B structure (Fe₃). It is demonstrated that binuclear units can introduce a large number of potential open metal sites, regulate framework stability, and optimize adsorption capacity, thereby enhancing the photocatalytic property of MOFs. Fe₃+Mg₂/PMS system showed a RhB removal efficiency of 97.5 % in 10 min under visible light irradiation, giving a degradation rate constant of 0.28 min⁻¹. In addition, the photocatalytic mechanism was also systematically investigated. This study provides a new clue for developing highly efficient and stable MOF-based catalysts for AOPs.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108056"},"PeriodicalIF":3.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of M (M = Sn and Ti) substitution for B-site on crystal structure and microwave dielectric properties of double perovskite-structured Sr2(SmNb)1-0.5xMxO6 ceramics","authors":"Akinori Kan ,&nbsp;Soma Naruse ,&nbsp;Susumu Takahashi","doi":"10.1016/j.solidstatesciences.2025.108062","DOIUrl":"10.1016/j.solidstatesciences.2025.108062","url":null,"abstract":"<div><div>The Sn substitution for Sm and Nb in Sr₂(SmNb)_{1-0.5<em>x</em>}Sn_<em>x</em>O₆ (SSNS) ceramics formed solid solutions over the whole composition range. The solubility limit of Ti substitution for Sm and Nb was <em>x</em> = 0.5 for Sr₂(SmNb)_{1-0.5<em>x</em>}Ti_<em>x</em>O₆ (SSNT) ceramics. Crystal structure refinement of SSNS and SSNT by the Rietveld method revealed that the crystal structure of SSNS changed from monoclinic (<em>P</em>2₁/<em>n</em>) to orthorhombic (<em>Pnma</em>) at <em>x</em> ≥ 0.5, while the crystal structure of SSNT changed from monoclinic to trigonal (<em>R</em>-3) at <em>x</em> = 0.5. At <em>x</em> ≥ 0.75, SrTiO₃ was detected as a secondary phase in SSNT ceramics. Such changes in the symmetry of crystal structure for SSNS and SSNT by <em>M</em> substitution for Sm and Nb were also suggested by broadening of Raman peaks, which corresponds to the symmetric <em>B</em>O₆ stretching vibration mode. The <em>M</em> substitution for Sm and Nb leads the decrease in the quality factor (<em>Q</em>・<em>f</em>) of SSNS and SSNT ceramics; the decrease in the degree of <em>B</em>-site ordering and morphological changes in these ceramics affects the <em>Q</em>・<em>f</em> values of the ceramics in single phase region. For SSNS ceramics, the <em>Q</em>・<em>f</em> values decreased from 35,732 GHz to 14,795 GHz, with a dielectric constant (ε_r) of 31.1–14.7 and the temperature coefficient of resonant frequency (<em>TCf</em>) of −55.9 to - 65.7 ppm/°C.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108062"},"PeriodicalIF":3.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A representation of crystal systems and space groups based on the variance of atomic positions (VAP): Case of 2D materials","authors":"R. Botella","doi":"10.1016/j.solidstatesciences.2025.108061","DOIUrl":"10.1016/j.solidstatesciences.2025.108061","url":null,"abstract":"<div><div>Material representation is an active topic of computational materials science. It is especially useful for crystal structure prediction as well as related properties such as formation energy and band structure. Material representations aim at encoding the material structure in a format that can be well understood by machine learning (ML) algorithms. Herein, a new material representation is proposed that is both compact and easily usable by ML algorithms. In the proposed representation, the connectivity and symmetry considerations of a material are made implicit, assimilating the unit cell of a material to a 3D cloud of points. Accordingly, one way to describe such a distribution of values is through the study of their variance. In the case of atomic positions, we obtain the variance of atomic positions (VAP). The VAP representations of 6176 2D materials from the 2DMatPedia database are computed and studied. After visual inspection, the VAP representations values obtained are sorted by crystal systems and space groups to be classified through ML. K-nearest neighbors (KNN) and random forest (RF) algorithms are trained and tested for crystal system and space group classification. Despite the visual inspection not showing VAP-crystal system or VAP-space group correlation, classification accuracies range from ca. 92 % to ca. 97 %, and from 96 % to 98 % for pairwise crystal system and pairwise space group classifications, respectively. Multi-classification accuracies are also high, ranging from 79 % to 88 % for crystal systems, and from 73 % to 82 % for space groups. To deepen the understanding of the classification process, accuracy maps are analyzed, uncovering a bias of the dataset. The influence of this bias on the classification accuracies is discussed.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108061"},"PeriodicalIF":3.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}