Vadim M. Kovrugin

National Graduate School of Engineering and Research Center (Caen) · CRISMAT

A series of Na7V3+4–xAlx(P2O7)4(PO4) (x = 0, 1, 2, and 4) materials were synthesized by flux crystal growth. Novel Na7V4–xAlx(P2O7)4(PO4) (x = 1, 2) compositions were structurally characterized by single crystal and powder X-ray diffraction analyses using laboratory and high-resolution synchrotron X-ray sources. The investigation of the electrochem...

Electrochemical tests demonstrated the original properties of the new layered Na3V(PO4)2 compound studied as a high voltage positive electrode.

The mixed Mn²⁺/V³⁺ Na‐super‐ionic‐conductor (NASICON) cathode material Na4MnV(PO4)3 is prepared by solid‐state reaction at 800 °C under argon. When used as a positive electrode in Na batteries, this material can exchange three electrons for two transition metals, that is, yielding a high gravimetric capacity of 156 mAh g⁻¹ on charge when the upper...

Crystal chemistry of the variscite and metavariscite groups: Crystal structures of synthetic CrAsO4⋅2H2O, TlPO4⋅2H2O, MnSeO4⋅2H2O, CdSeO4⋅2H2O and natural bonacinaite, ScAsO4⋅2H2O - Uwe Kolitsch, Matthias Weil, Vadim Kovrugin, Sergey V. Krivovichev

The crystal chemistry and the electrochemical properties of Na7V3(P2O7)4 as a high voltage cathode material upon Na⁺ extraction/insertion were investigated. The crystal structure was solved and refined for the first time from single crystal X-ray diffraction data. Possible sodium migration pathways were determined using the bond valence energy land...

Birnessite δ-MnO2, with its low cost, high theoretical capacity, and stable cycling performance in aqueous electrolytes, holds promise as an electrode material for high-power and cost-effective electrochemical energy storage devices. To address its poor electronic conductivity, we incorporated environmentally friendly iron into birnessite and condu...

Alkali copper sulfates form a rapidly developing family of inorganics. Herein, we report synthesis and crystal structure, and evaluate possible ion migration pathways for a novel Na-K-Cu anhydrous sulfate, K(Na,K)Na2[Cu2(SO4)4 ]. The CuO7 and SO4 polyhedra share common vertices and edges to form [Cu2(SO4)4] ⁴⁻ wide ribbons, which link to each other...

Two-dimensional (2D) electron back scattered diffraction (EBSD) is a powerful tool for microstructural characterization of crystalline materials. EBSD enables visualization and quantification of the effect of synthesis methods on the microstructure of individual grains, thus correlating the microstructure to mechanical and electrical efficiency. Th...

Two novel compounds, K2Cu3(SO4)4 and KNaCu(SO4)2, were synthesized. The crystal structure of K2Cu3(SO4)4 is based on a [Cu3(SO4)4] framework with relatively simple bond topology, but with four different CuOn polyhedron geometries. The K+ cations reside in the pores of the framework. The [Cu(SO4)2] framework in KNaCu(SO4)2 encloses large elliptical...

Anhydrous sulfate minerals are abundant in the active fumaroles with highly oxidizing conditions on the scoria cones of the Tolbachik volcano. The mineral itelmenite, ideally Na2CuMg2(SO4)4, containing isomorphous admixture of Zn, was described in 2018, whereas glikinite, ideally Zn3O(SO4)2, was described in 2020. Synthetic analogs of both minerals...

Comparison of the natural and synthetic phases allows an overview to be made and even an understanding of the crystal growth processes and mechanisms of the particular crystal structure formation. Thus, in this work, we review the crystal chemistry of the family of uranyl selenite compounds, paying special attention to the pathways of synthesis and...

The new mineral antofagastaite, ideally Na 2 Ca(SO 4 ) 2 ·1.5H 2 O, was found in the oxidation zone of sulfide–quartz veins at the abandoned Coronel Manuel Rodríguez mine, Mejillones, Antofagasta Province, Antofagasta Region, Chile. It is associated with sideronatrite, metasideronatrite, aubertite, gypsum, ferrinatrite, glauberite, amarillite and a...

Single crystals and polycrystalline samples of a synthetic analogue of saranchinaite, Na2Cu(SO4)2, have been prepared by two different methods. The structural analysis revealed unusual heptahedral CuO7 coordination [4+1+2] of Cu²⁺ cations in its crystal structure. The title compound crystallizes in the non-centrosymmetric space group P21 and exhibi...

Extensive experiments in the Pb–Cu–Se–O–Br system at 400°C yielded single crystals of nine new compounds (Cu ²⁺ Pb 6 (SeO 3 ) 4 Br 6 , Cu ²⁺ Pb 2 (SeO 3 ) 2 Br 2 , Cu ²⁺3 Pb 2.4 (SeO 3 ) 5 Br 0.8 , Cu ²⁺2 Pb(SeO 3 ) 2 Br 2 , Cu ²⁺4 Pb(SeO 3 ) 4 Br 2 , [Cu ²⁺9 Pb 2 O 4 ](Cu ⁺ Br 2 )(SeO 3 ) 4 Br 5 , [Cu ²⁺7 PbO 3 ](Cu ⁺ Br) 0.35 (SeO 3 ) 3 Br 4 , [C...

Single crystals of new Mn 2 [Bi 2 O](SeO 3 ) 4 ( I ), MnBi(SeO 3 ) 2 Cl ( II ), Mn II Mn III (SeO 3 ) 2 Cl ( III ), Mn 5 (SeO 3 ) 2 Cl 6 ( IV ), and Mn 4 (Mn 5 ,Bi)(SeO 3 ) 8 Cl 5 ( V ) have been synthesized by chemical vapour transport and hydrothermal methods. They have been structurally characterized by single crystal X-ray diffraction analysis....

The new mineral saranchinaite, ideally Na2Cu(SO4)2, was found in sublimates of the Saranchinaitovaya fumarole, Naboko Scoria Cone, Tolbachik volcano, Kamchatka, Russia. Its discovery and study allowed to characterize the thermal decomposition of kröhnkite and provided an insight into the high-temperature behavior of other kröhnkite-type materials....

Embreyite from the Berezovskoe deposit was studied by the means of powder XRD, single-crystal XRD, IR spectroscopy and microprobe analysis. The empirical formula of embreyite obtained on the basis of microprobe analysis is Pb1.29Cu0.07Cr0.52P0.43O4 (without taking into account presence of H2O). An examination of single-crystal XRD frames of the tes...

Polyanionic-type materials have a wider variety of crystal architectures compared to structurally simple transition metal oxides, thus leading to a huge diversity of possible structural features beneficial to some specific electrochemical properties of the batteries [1, 2]. In particular, the 4-, 5-, and 6-fold coordinations and various oxidation s...

Single crystals of a new lead cobalt phosphite, PbCo2(HPO3)3, have been synthesized using mild hydrothermal techniques and characterized by X-ray diffraction analysis, SQUID magnetic measurements, IR spectroscopy, UV–vis spectroscopy, thermogravimetric analysis, and scanning electron microscopy. PbCo2(HPO3)3 crystallizes in the non-centrosymmetric...

Provided for non-commercial research and educational use only. Not for reproduction or distribution or commercial use. This article was originally published in a journal published by Elsevier in cooperation with Mendeleev Communications, and the attached copy is provided for the author's benefit and for the benefit of the author's institution, for...

Due to the low and close melting and sublimation temperatures (340 and 350 °C, respectively), the crystal growth of selenates and/or selenites is generally achieved using either chemical vapor transport routes, hydrothermal methods due to the good solubility and reactivity of (SeO3)2– anions or isothermal evaporation synthesis. Here we report examp...

Pottsite from the Linka mine (Nevada, USA) was studied by scanning electron microscopy, energy- and wavelengthdispersive analyses, and single-crystal X-ray diffraction. The formula, calculated on the basis of (V + As) = 4, shows that the Pb/Bi atomic ratio in pottsite varies between 0.86 and 1.48, and a plot of Pb vs. Bi (atoms per formula unit) su...

Two novel copper selenite chlorides, K[Cu3O](SeO3)2Cl (I) and Na2[Cu7O2](SeO3)4Cl4 (II), have been synthesized by the CVT method. Their crystal structures have been solved by direct methods and refined by least-squares techniques. I is triclinic, space group P1, a = 7.6821(5), b = 8.1179(5), c = 8.7836(6) Å, α = 113.193(3), β = 108.735(4), γ = 98.2...

Our recent exploration of the Pb-Ni-Se-O “crystallization phase diagram” in hydrothermal conditions has led to the discovery of three new selenites. Here we have applied a similar systematic method to the Pb-V-Se-O system using both hydrothermal and CVT crystal growth using either PbO or PbCl2 as the source of lead. In our approach, phases in prese...

The abilities of the (HPO3)2– and (SeO3)2– anions as structure building units and as spin exchange paths between magnetic ions were investigated by preparing and analyzing the isostructural Fe2(SeO3)3 and Fe2(HPO3)3. In both compounds, the face-sharing Fe2O9 dimers are interconnected into chains by the (HPO3)2– and (SeO3)2– anions. The (HPO3)2– is...

The K- and Na-synthetic analogues of the fumarolic mineral ilinskite have been synthesized by the chemical vapor transport (CVT) reactions method. The A[Cu5O2](SeO3)2Cl3 (A + = K+, Na+) compounds crystallize in the orthorhombic space group Pnma: a = 18.1691(6) Å, b = 6.4483(2) Å, c = 10.5684(4) Å, V = 1238.19(7) Å3, R 1 = 0.018 for 1957 unique refl...

Single crystals of seven novel uranyl oxysalts of selenium with protonated methylamine molecules, [C2H8N]2[(UO2)(SeO4)2(H2O)] (I), [C2H8N]2[(UO2)2(SeO4)3(H2O)] (II), [C4H15N3][H3O]0.5[(UO2)2(SeO4)2.93(SeO3)0.07(H2O)](NO3)0.5 (III), [C2H8N]3[H5O2][(UO2)2(SeO4)3(H2O)2]2(H2O)5 (IV), [C2H8N]2[H3O][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)0.2 (V), [C4H12N]3[H3...

Chemical vapor transport (CVT) reactions were used to prepare three modular mixed-valent Cu(I)–Cu(II) compounds, (Pb2Cu2+9O4)(SeO3)4(Cu+Cl2)Cl5 (1), (PbCu2+5O2)(SeO3)2(Cu+Cl2)Cl3 (2), and (PbxCu2+(6–x)O2)(SeO3)2(Cu+Cl2)K(1–x)Cl(4–x) (x = 0.20) (3). In their crystal structures chains of anion-centered (OCu2+4) and (OCu2+3Pb) tetrahedra form honeycom...

The PbO-NiO-SeO2 ternary system was fully studied using constant hydrothermal conditions at 473 K. It yields the establishment of the corresponding phase diagram using a systematic assignment of reaction products by both powder and single-crystal X-ray diffraction. It leads to the preparation of three novel lead nickel selenites, α-PbNi(SeO3)2 (I),...

Single crystals of [NaCl][Cu(HSeO3)2] have been prepared by the chemical vapor transport reactions. Its crystal structure (monoclinic, C2/c, a = 13.9874(7), b = 7.2594(4), c = 9.0421(5) Å, β = 127.046(2)°, V = 732.81(7) Å3) is based upon electroneutral [Cu(HSeO3)2] sheets formed by corner sharing between the [CuO4] squares and (HSeO3) groups that a...

The reactions between PbO, Bi2O3 (or BiOCl), and SeO2 by the chemical vapor transport method using HCl as a transporting agent afforded three novel bismuth/lead chloroselenites, namely, β-BiSeO3Cl (1), Bi6(SeO3)4Cl10 (2), and PbBi10(SeO3)12Cl8 (3). Compound 1 is noncentrosymmetric (space group Cc, SHG active) and has a giant unit cell (V = 19792(2)...

Single crystals of eight novel uranyl selenates, (CH3NH3)2[(UO2)(SeO4)2(H2O)](H2O) (I) and (CH3NH3)2[(UO2)(SeO4)2(H2O)] (II), (CH3NH3)2[(UO2)2(SeO4)3] (III) and (CH3NH3)(H3O)[(UO2)2(SeO4)3(H2O)](H2O) (IV), (CH3NH3)4[(UO2)3(SeO4)5](H2O)4 (V) and (CH3NH3)(H5O2)(H3O)2[(UO2)3(SeO4)5](H2O)4 (VI), (CH3NH3)4(H3O)2[(UO2)5(SeO4)8(H2O)](H2O)4 (VII), and (CH3...

The crystal structure of the new organically templated uranyl selenite-selenate [C2H8N][(H5O2)(H2O)][(UO2)2(SeO4)3(H2SeO3)](H2O) is based upon complex layers with a unique topology, which was not observed previously in inorganic compounds.