Two diamonds of cubic habit from the Ebelyakh River placer, Yakutia, with many oriented needle inclusions, were studied. A wide range of methods has been used, including optical (absorption luminescence and Raman spectroscopy), black-and-white and color cathodoluminescence (CL), X-ray analysis, magnetic investigations and selective etching. According to Raman spectroscopy, X-ray analysis, and magnetic measurements, inclusions are formed by iron oxides (magnetite, hematite). IR measurements show a high degree of aggregation of the structural nitrogen impurity, which is mainly represented by form A, in a subordinate amount by form B, nitrogen in form C remained in insignificant quantities. In color cathodoluminescence, an ordered arrangement of optically active centers is visible at high magnification. Cathodoluminescence in black and white allows us to see two stages of crystal development. At the first stage, the crystals grew as ordinary highly defective cuboids with zonal and sectoral structures. At the second stage the crystals were deeply annealed, their structure was “refined”, dislocations from the crystal volume were redistributed into flat clusters mainly in places of concentration of needle inclusions, structural impurity nitrogen is aggregated, incoherent impurities, mainly represented by iron, are mobilized into needle inclusions. The conditions for the formation of such diamonds and their two-stage history are discussed. It is assumed that deep annealing at the second stage of diamond existence is associated with further immersion to a depth in high-temperature conditions that ensure the annealing of diamonds and their structural order.

Radiation testing of perspective materials by fast neutron flux is an important task for large physical facilities such as the Large Hadron Collider or the International Thermonuclear Experimental Reactor. Such a source of fast neutrons is the accelerator based neutron source VITA, proposed, developed and actively used at the Budker Institute of Nuclear Physics. The paper describes the accelerator based neutron source VITA, its features related to the generation of a powerful fast neutron flux, the result of a long lasting experiment with fast neutron generation, further plans to increase the energy and current of the deuteron beam, to develop a compact fast neutron generator, and to increase the total fast neutron yield to 2.1013 s- 1. The paper presents results of the perspective materials irradiation by fast neutrons flux.

The crystal structures of two new palladium complexes with 4-methylamino-3-penten-2-one CH3C(NHCH3)CHC(O)CH3 (Hmki) are determined. The crystals β-trans-Pd(mki)2 (1) and Pd(ki) (mki)·0.5(C6H6) (2) (ki = CH3C(NH)CHC(O)CH3, mki = CH3C(NCH3)CHC(O)CH3). The crystals belong to the triclinic system with the following unit cell parameters for 1: space group P1̅ , a = 7.1877(3) Å , b = 7.2668(4) Å, c = 7.3246(3) Å, α = 83.903(1)°, β = 61.263(1)°, γ = 74.197(1)°, V = 322.64(3) Å3, Z = 1; for 2: space group P1̅ , a = 7.1787(2) Å, b = 9.4578(4) Å, c = 12.1817(7) Å, α = 108.361(1)°, β = 96.160(1)°, γ = 107.046(1)°, V = 732.09(6) Å3, Z = 2. The complexes have molecular structures composed of isolated Pd(mki)2 and Pd(ki)(mki) molecules in 1 and 2 respectively. The electron density distribution in α-trans-Pd(mki)2, β-trans-Pd(mki)2 (1) and mixed-ligand Pd(ki)(mki)·0.5(C6H6) (2) complexes is studied by quantum chemical calculations using the density functional theory. The topological analysis reveals that the electron density distributions are similar in both α- and β-trans-Pd(mki)2 complexes. Based on the analysis of intermolecular interactions it is shown that different molecular geometries of the α and β modifications of trans-Pd(mki)2 results in differences in structure-forming intermolecular contacts and consequently, affects the crystal molecular packing.

Bulk Na6Mo11O36 single crystals with dimensions 70*40*20 and 70*40*40 mm3 were obtained by the low-thermal gradient Czochralski technique. The uniformity of the grown boules was assessed using the following characterization techniques: X-ray diffraction (XRD) and differential scanning calorimetry. The crystal structure was thoroughly examined through single-crystal X-ray diffraction (SCXRD). Space group was determined by SCXRD as C2/c (a = 7.2229(1) & Aring;, b = 17.8065(4) & Aring;, c = 22.2789(5) & Aring;, beta = 90.311(1)degrees). Na6Mo11O36 crystals exhibited a strong tendency to formation of twins up to the change of crystallization direction on 90 degrees during the growth process, which is a unique event for Czochralski technique crystal growth. Crystal faceting was studied, and Miller indexes of developed facet families were determined by the XRD method; a reference model of the Na6Mo11O36 crystal was visualized based on obtained data. Optimal growth direction for obtaining uniform bulk Na6Mo11O36 crystals was determined to be [010]. Photoluminescence was registered on a 10 x 10 x 10 mm3 sample from 175 K temperature and below.

Single crystals of Fe(dpm)3 (dpm - dipivaloylmethanate) are analyzed by X-ray diffraction in the temperature range of 90-365 K. A new crystal modification is found in the range of 90-100 K (space group P1̅ , Z = 8); a phase transition is confirmed to occur at 230 K (space group P1̅ , Z = 4). In the range of 250-365 K, a relative increase in the monoclinic unit cell parameters (space group C2/c, Z = 8) is Δa/a = 0.67

A technique for refining unit cell parameters of crystals belonging to arbitrary systems on modern single-crystal diffractometers is described. The technique is based on the 2D-detector position calibration. The elementary orthorhombic unit cell parameters of the α-33S single crystal have been refined. The anisotropy of change in the parameters in the range of 90–350 K has been analyzed. The relative increase in the parameter c is shown to be 6.4

An original procedure is proposed to refine unit cell parameters (UCPs) of single crystals in Bond’s scheme. The procedure involves the use of a modern laboratory diffractometer equipped with a 2D detector and a three-circle goniometer. At the first stage, preliminary UCPs, diffraction class, and crystal orientation relative to goniometer axes are determined. Then φ and ω angles are calculated to bring an appropriate (occurrence of a well-resolved doublet, intensity) reflection hkl on the equatorial plane. The measurement in Bond’s scheme is carried out at two symmetric positions of the detector ±2θD ≈ 2θhkl. The principal difference from the measurement on a single crystal spectrometer consists in refusing to plot the reflection profile I(ω) and passing to ω-scans with a width of 3-4°, which allows the measurement of the Kα1/Kα2 doublet profile. After its processing by two independent 2D functions, coordinates of the maxima are determined, and then the 4θhkl. Angle is found based on angular sizes of the detector pixel and the difference in the coordinates of X Kα1-component reflections obtained in symmetric positions. In this approach, measurement errors are related to the accuracy of placing the detector in two symmetric positions and the correctness of processing 2D reflection profiles. In the study of reference Si and Ge single crystals in the range of 2θD angles close to 100°, UCP deviations from the theoretical values are found to not exceed 0.0004 Å, and the relative measurement accuracy is 6·10–5. The refinement of UCPs of single crystals grown in the Y2O3–Eu2O3 system by the melt-solution technique indicates the formation of the (Y1–xEux)2O3 solid solution with the x value range of 0.27-0.40. A scheme is proposed to improve the measurement accuracy when the procedure is transferred to the diffractometer with synchrotron radiation.

Предложен ряд подходов к уточнению параметров элементарных ячеек монокристаллов на серийных лабораторных дифрактометрах, оснащенных 2D-детекторами, и соответствующий математический аппарат для обработки полученных результатов. Их использование продемонстрировано на примере ромбических кристаллов LiCsMo3O10, выращенных низкоградиентным методом Чохральского при двух разных ориентациях затравок, рентгеноструктурный анализ показал их тождественность. Показано, что параметры элементарных ячеек кристаллов совпадают в пределах оцененной погрешности измерений. Проведено исследование температурного хода параметров элементарной ячейки в диапазоне температур 90-450 К, установлен вид элементов тензора теплового расширения. Обсуждены изменения структурных характеристик LiCsMo3O10 в указанном температурном диапазоне.

A technique for arbitrary symmetry crystals unit cell parameters refining on modern single-crystal diffractometers is described. The technique is based on the 2D detector position calibration. The elementary orthorhombic unit cell parameters of the α-33S single crystal have been refined. The anisotropy of parameters changes in the range of 90–350 K has been studied. It is shown that the relative increase in parameter c is 6.4%. The obtained dependences are approximated by second–third degree polynomials. The absolute increase in cell volume is 138.4 A3, and the relative increase is 4.3%. The temperature dependencies of the thermal expansion tensor elements has been refined. The coefficients of α-33S thermal expansion tensor at the room temperature are: α11 = 15.35 × 10–5, α22 = 8.56 × 10–5, α33 = 9.12 × 10–5 К–1.

Carbonado is a specific variety of diamonds, typical representatives of which are distributed in the diamond placers of Central Africa, Brazil, and Venezuela. Carbonado consists of the microcrystalline aggregates of diamonds, with inclusions of mineral matter. These aggregates appear as fragments that are rounded to varying degrees. Carbonado has been known for a long time, but its primary sources have not been found and its genesis remains unclear. We have substantiated the hypothesis that the most probable precursor of carbonado is shungite. Shungite is a specific form of non-crystalline, non-graphitic, fullerene-like carbon. Shungite rocks, currently known in Karelia (Russia), are natural microdispersed composite materials containing shungite—carbonaceous matter and mineral components of different compositions. The content of carbonaceous matter in shungite rocks is from less than 10% to 98%. The carbon isotopic composition of shungite is light ẟ13C from −25‰ to −40‰. The age of shungite rock is more than 2 billion years old, but earlier shungite was probably much more widespread. Known shungite rocks are more than 2 billion years old, but earlier shungite was probably much more widespread. Shungite rocks could recrystallize into diamond rock upon subduction to high pressure and temperature. The diamond rocks could then be exhumed to the Earth’s surface, where they could undergo disruption and reworking with formation of those very fragments that are known as “carbonado”.

A specific regime of continuous slow cooling of melted isocubanite CuFe2S3 from 1020 °C to 638 °C is realized, and then the crystallized ingot is quenched. This regime ensures both equilibrium crystallization of primary phases and their subsequent non-equilibrium solid-phase transformations. A large series of samples cut along a 90 mm long ingot are studied by optical and electron microscopy, powder XRD, and the stoichiographic differential dissolution method. Phase compositions are determined by the electron microprobe analysis. It is established for the first time that isocubanite releases cubic chalcopyrite rather than tetragonal one upon cooling in the following order: first cationic ordering of the isocubanite matrix and then steady metastable coherent pre-precipitations of cubic chalcopyrite in the matrix to finally transform into polycrystals free from the matrix.

Abstract Hybrid composites of gold nanoparticles (Au NPs) with polymer hydrogels are promising platforms for the development of new materials that can respond to external stimuli (chemical, physical, mechanical), reversibly absorb/release water and reagents, act as plasmonic sensors, and also be triggers of photochemical processes and photothermal actuators of micromechanical processes. In our study we have (1) proposed a one-step method for the synthesis of a hybrid composite of Au NPs with polyacrylamide hydrogel (PAAm) by the reduction of HAuCl 4 with acrylamide (AAm) and simultaneous radical polymerization of AAm in an aqueous solution, (2) optimized the conditions for obtaining a phase-stable product, (3) studied the effect of the initial concentrations of Au and AAm on the morphology and structure of Au NPs, (4) obtained and characterized plasmonic films from the Au NPs-PAAm composite and after thermal removal of the polymer matrix. The methods of UV-visible and photon correlation spectroscopy, X-ray diffraction, synchronous thermal analysis, transmission and scanning electron microscopy were used in the work. Graphical abstract

Hybrid composites of gold nanoparticles (Au NPs) with polymer hydrogels are promising platforms for the development of new materials that can respond to external stimuli (chemical, physical, mechanical), reversibly absorb/release water and reagents, act as plasmonic sensors, and also as catalysts for photochemical processes and photothermal actuators of micromechanical processes. We proposed a one-step synthesis of a hybrid composite of Au NPs doped into polyacrylamide (PAAm) hydrogel by reducing HAuCl4 with acrylamide (AAm) and simultaneous radical polymerization of AAm, initiated by (NH4)2S2O8, in the aqueous solution. The influence of initial concentrations of 0.26–10 mM Au and 0.1–1 M AAm on the morphology and structure of Au NPs, as well as on the phase stability of the products, was studied. At concentrations of 3 mM Au, 1 M AAm and 1.2 mM (NH4)2S2O8, а temperature of 60 °C and a heating time of 6 h, a stable product with a clearly defined SPR band with a maximum at 552 nm was obtained. It contained polycrystalline Au NPs in the form of spheroids, cuboctahedra, and rods up to 100 nm size. The product was used to obtain plasmonic films of Au NPs-PAAm composite after drying at 100 °C and gold after thermal removal of the polymer matrix at 550 °C.The work used UV-visible and photon correlation spectroscopy, X-ray diffraction, synchronous thermal analysis, transmission and scanning electron microscopy.

A fine crystalline sample of the cubic modification (space group Ia3̅ , Z = 16) of gadolinium oxide (C-Gd2O3) is grown by the solution–melt technique. The single crystal X-ray diffraction analysis performed at 150 K and 298 K reveals a relative increase in the unit cell parameter by 0.08

We report a comparative crystal chemical analysis of volatile homoligand complexes of Co(II), Ni(II), Cu(II), Pd(II), and Pt(II) with β-ketoimines utilized as precursors in the preparation of oxide and metal film coatings for various purposes using chemical vapor deposition. The crystal structures and intermolecular interactions of β-ketoiminates with the general formula M(L)2 (L = (R1-C(O)CH-C(N-R3)-R2)2; R1, R2 = CH3, CF3, C(CH3)3, C(OCH3)(CH2)2 in various combinations; R3 = H, CH3) are studied.

The milestones of the development of X-ray diffraction and crystal chemical studies in the Laboratory of Crystal Chemistry of the Nikolaev Institute of Inorganic Chemistry SB RAS for 1958-2024 are highlighted.

Synthesis of diamond from anthracene in an Fe,Ni-melt at 5.5 GPa and 1450 °C.

We propose a number of approaches for refining unit cell parameters of single crystals using serial laboratory diffractometers equipped with 2D detectors and discuss the corresponding mathematical apparatus for processing the obtained results. The approaches are demonstrated on the example of orthorhombic LiCsMo 3 O 10 crystals grown by the low-gradient Czochralski method using two different seed orientations but being identical in terms of the XRD analysis. It is shown that unit cell parameters of the crystals coincide within the estimated measurement error. The temperature dependence of unit cell parameters in the temperature range 90-450 K is studied, the view of the elements of the thermal expansion tensor is determined. The changes in the structural characteristics of LiCsMo 3 O 10 in the studied temperature range are discussed.

Проведено рентгеноструктурное исследование монокристаллов Fe(dpm)3 (dpm – дипивалоилметанат) в интервале температур 90-365 K. Обнаружена новая кристаллическая модификация в интервале 90-100 K (пр. гр. Р, Z = 8), подтвержден фазовый переход при 230 K (пр. гр. Р, Z = 4). В диапазоне 250-365 K относительное увеличение параметров моноклинной ячейки (пр. гр. C2/c, Z = 8) составило Δa/a = 0.67, Δb/b = 1.16 и Δc/c = 0.47 %, угол  уменьшился на 3,3 %. В интервале 90-365 K относительное увеличение объема, приходящегося на одну молекулу, составило 6.65 %, причем средние значения расстояний Fe-O и хелатных углов O-Fe-O практически не изменились. Построены поверхности Хиршвельда для структур при температурах: 90, 130, 250 и 365 K. Изучены слои Fe(dpm)3, полученные напылением в вакууме (PVD) и кристаллизацией раствора при центрифугировании (spin coating) на разных неорганических подложках, установлена ориентация и проведен анализ особенностей структуры в направлениях [100] и [001].

A new approach to the precision determination of single-crystal unit cell parameters is proposed and demonstrated using tetragonal Ag0.8Li0.2InSe2.