Background: Synthesis of metal oxides nanoparticles with specific morphology and size has become the subject of many experimental protocols. Biosynthesis of the nanoparticles using plants is more preferable than physical and chemical methods because of its environmental friendliness.Objective: The purpose of this study was to report the potential for green synthesis of cerium oxide nanoparticles using plant extracts with a high content of phenolic metabolites.Methods: We have synthesized the CeO2 nano- and microparticles using Petroselinum crispum aqueous extract. The particles were characterized by UV-visible spectroscopy, IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and dynamic light scattering analysis. For detection the reduction capacity of the extract the evaluation of total phenolic and flavonoid content as well as high-performance liquid chromatography-mass spectrometry (HPLC-MS) were performed. Biological activity of the particles was identified by bioluminescent tests and bio tests with Triticum vulgare.Results: Testing on T. vulgare showed that biogenic cerium dioxide powders stimulated the growth of up to 5-11,4% relative to intact samples, significantly increased the length of the leaves of seedlings and the root length. When seedings were exposed to the biosynthesized CeO2 particles, the level of chlorophylls was more stable and even slightly higher than control. Noticeable protective properties of the biosynthesized CeO2 powder under oxidation conditions were observed on the plant T. vulgare after a brief exposure (from 4 to 24 h).Conclusion: Thus, biogenic CeO2 can be potentially utilized in oxidative damage protection of agricultural plants.

Centimeter-sized crystals of orthorhombic calcium formate, α-Ca(HCO₂)₂ from Alkali Lake, Oregon, USA have been studied by means of powder and single-crystal X-ray diffraction analysis, infrared, and Raman spectroscopy. Based on the data on carbon isotope abundance in calcium formate and associated minerals, it was concluded that the formation of α-Ca(HCO₂)₂ may be a result of a combination of two factors: lake microbial metabolism and anthropogenic pollution with Agent Orange. Possible causes of stability of the low-density tetragonal β-Ca(HCO₂)₂ polymorph (formicaite) in boron ores are discussed.

The new eudialyte-group mineral, odikhinchaite, was discovered in a peralkaline pegmatite vein hosted by melteigite at the Odikhincha ultrabasic alkaline–carbonatite intrusion, Taimyr Peninsula, Krasnoyarsk Krai, Russia. Associated minerals are orthoclase, albite, aegirine, cancrinite, ancylite-(Ce), catapleiite, and wadeite. Odikhinchaite occurs as dense rosette-like aggregates up to 11 mm across, consisting of split lamellar individuals. The mineral is translucent to transparent, deep purple, with vitreous luster. Odikhinchaite is brittle, with uneven fracture; distinct cleavage on (001) is observed. Hardness determined by the micro-indentation method is equal to 430 kgf/mm²; the Mohs hardness is 5. D(meas.) is 2.97(1) g·cm⁻³, D(calc.) is 3.04 g·cm^–3. Odikhinchaite is optically uniaxial (–), ω = 1.638(2), ε = 1.630(2). The IR spectrum shows the presence of the ^IVMn²⁺O₄ polyhedra, H₂O molecules and CO₃^2– anions. The chemical composition is (electron microprobe, H₂O determined by the modified Penfield method, CO₂ determined by selection sorption of gaseous annealing products; wt%): Na₂O 9.25, K₂O 0.59, CaO 12.77, MnO 5.49, FeO 0.75, MgO 0.24, La₂O₃ 0.38, Ce₂O₃ 0.39, Nd₂O₃ 0.15, Al₂O₃ 0.07, SiO₂ 44.80, ZrO₂ 11.13, TiO₂ 0.07, Nb₂O₅ 4.17, Cl 0.69, CO₂ 0.90, H₂O 2.22, –O = Cl –0.16, total 99.72. The crystal structure was solved using single-crystal X-ray diffraction data. Odikhinchaite is trigonal, space group R3m; the unit-cell parameters are: a = 14.2837(2) Å, c = 30.0697(3) Å, V = 5313.04(12) ų. The new mineral is isostructural with other 12-layered members of the eudialyte group with the space group R3m. Its crystal chemical formula is (Z = 3): {^N1(Na_2.58Ca_0.42)^N2[Na_2.37Ca_0.51(H₂O)_0.12]^N3(Sr_2.00K_0.45Na_0.35REE_0.20)^N4Na₃^N5[(H₂O)_1.8Na_1.2]}{^ZZr₃^M1Ca₆^M2(Mn_2.49Fe²⁺_0.51)[^M3Nb(OH)_1.82O_1.18](^M4SiOH)[Si₃O₉]₂[Si₉O₂₇]₂^X1[(CO₃)_0.53Cl_0.47]^X2[(H₂O)_0.6(O,F)_0.4]^XM4(CO₃)_0.15. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 11.42 (64) (101), 4.309 (41) (205), 3.405 (53) (131), 3.208 (45) (208, 036), 3.167 (44) (217), 2.978 (100) (315), 2.858 (86) (404).

Synthetic alumosilicates are used in many industrial applications, and the synthesis of clay minerals under different conditions allows us to understand the conditions of their formation. This study examined the impact of varying silica precursors, pH conditions and synthesis durations. Synthetic kaolinite group mineral analogues were investigated by X-ray diffraction, scanning electron microscopy and infrared spectroscopy. Additionally, the crystallinity index was calculated. The impact of using different silica sources on the structural features of synthetic kaolinite group analogues was revealed. The use of a Nanosil precursor resulted in the formation of highly crystalline kaolinite. The most significant alterations in the course of synthesis were observed at different pH values. The formation of various synthetic analogues of minerals from the kaolinite group was observed: at a high pH, the formation of halloysite with a small admixture of kaolinite was observed. Conversely, the synthesis resulted in the formation of ordered kaolinite at a low pH. The crystallinity index of the resulting synthesized kaolinite analogues rises as the synthesis duration increases, while the quantity of non-crystallized material decreases. The changes in the crystallinity of kaolinite when using different silica precursors are related to the different homogenization of the material that occurs at the stage of alumosilica gel formation.

Crystal-chemical features of a sulfide-bearing variety of the cancrinite-group mineral balliranoite from the Tuluyskoe lapis lazuli deposit, Baikal Lake area, Siberia, Russia, have been investigated using a multimethodic approach based on infrared (IR), Raman, and electron spin resonance (ESR), as well as ultraviolet, visible and near infrared (UV–Vis–near IR) absorption spectroscopy methods, luminescence spectroscopy, electron microprobe analysis, selective sorption of CO₂ and H₂O from annealing products, and single-crystal X-ray structure analysis. Holotype balliranoite and its sulfate analogue, davyne, were studied for comparison. The crystal-chemical formula of the studied sample from Tultuyskoe is Na_5.4K_0.1Ca_2.4(Si₆Al₆O₂₄)Cl₂[(CO₃)_0.7(SO₄)_0.18S*_0.95Cl_0.1(H₂O)_0.16], where the content of the wide zeolite channel is given in square brackets; S* is total sulfide sulfur occurring as disordered S₂^●−, cis- and trans-S₄, S₅²⁻, minor S₃^●−, and HS⁻ groups. The presence of S₅²⁻ and HS⁻ groups, the absence of CO₂ molecules, and the association with pyrrhotite and Fe-free pargasite indicate that the studied sample crystallized under highly reducing, low-temperature conditions, unlike holotype balliranoite whose formation was related to the Somma-Vesuvius volcanic complex, Italy. Irradiation of balliranoite from Tultuyskoe with X-rays results in the transformations of polysulfide groups other than S₃^●− into S₃^●− in accordance with the scheme: S₅²⁻ → S₂^●− + S₃^●−; 3S₂^●− → 2S₃^●− + e⁻; S₄ + S₂^●− + e⁻ → 2S₃^●−; S₄ + S₂^●− + e⁻ → 2S₃^●−; S₄ + S₅²⁻ + e⁻ → 3S₃^●− (e⁻ = electron).