Uakitite was observed in small troilite–daubréelite (±schreibersite) inclusions (up to 100 µm) and in large troilite–daubréelite nodules (up to 1 cm) in Fe-Ni-metal (kamacite) of the Uakit iron meteorite (IIAB), Republic of Buryatia, Russia. Such associations in the Uakit meteorite seemed to form due to high-temperature (>1000 °C) separation of Fe-Cr-rich sulfide liquid from Fe-metal melt. Most inclusions represent alternation of layers of troilite and daubréelite, which may be a result of solid decay of an initial Fe-Cr-sulfide. These inclusions are partially resorbed and mainly located in fissures of the meteorite, which is now filled with magnetite, and rarely other secondary minerals. Phase relations indicate that uakitite is one of the early minerals in these associations. It forms isometric (cubic) crystals (in daubréelite) or rounded grains (in schreibersite). The size of uakitite grains is usually less than 5 μm. It is associated with sulfides (daubréelite, troilite, grokhovskyite), schreibersite and magnetite. Carlsbergite CrN, a more abundant nitride in the Uakit meteorite, was not found in any assemblages with uakitite. Physical and optical properties of uakitite are quite similar to synthetic VN: yellow and transparent phase with metallic luster; Mohs hardness: 9–10; light gray color with a pinky tint in reflected light; density (calc.) = 6.128 g/cm³. Uakitite is structurally related to the osbornite group minerals: carlsbergite CrN and osbornite TiN. Structural data were obtained for three uakitite crystals using the electron backscatter diffraction (EBSD) technique. Fitting of the EBSD patterns for a synthetic VN model (cubic, Fm-3m, a = 4.1328(3) Å; V = 70.588(9) ų; Z = 4) resulted in the parameter MAD = 0.14–0.37° (best-good fit). Analytical data for uakitite (n = 54, in wt. %) are: V, 71.33; Cr, 5.58; Fe, 1.56; N, 21.41; Ti, below detection limit (<0.005). The empirical formula (V_0.91Cr_0.07Fe_0.02)_1.00N_1.00 indicates that chromium incorporates in the structure according to the scheme V³⁺ → Cr³⁺ (up to 7 mol. % of the carlsbergite end-member).

Nataliakulikite, Ca₄Ti₂(Fe³⁺,Fe²⁺)(Si,Fe³⁺,Al)O₁₁, is a mineral intermediate between perovskite CaTiO₃ and brownmillerite Ca₂(Fe,Al)₂O₅. It was discovered as a minor mineral in a high-temperature pyrometamorphic larnite-gehlenite rock at the Nahal Morag Canyon of the Hatrurim Basin, Israel. Nataliakulikite is associated with larnite, flamite, gehlenite, magnesioferrite, Fe³⁺-rich perovskite, fluorapatite, barite, Hashemite, and retrograde phases (afwillite, hillebrandite, portlandite, calcite, ettringite, hydrogarnet, and other hydrated Ca-silicates). The mineral forms brown subhedral or prismatic grains (up to 20 µm) and their intergrowths (up to 50 μm). Its empirical formula (n = 47) is (Ca_3.992Sr_0.014U_0.004)(Ti_1.933Zr_0.030Nb_0.002) (Fe³⁺_0.610Fe²⁺_0.405Cr_0.005Mn_0.005)(Si_0.447Fe³⁺_0.337Al_0.216)O₁₁ and shows Si predominance in tetrahedral site. The unit-cell parameters (HRTEM data) and space group are: a = 5.254, b = 30.302, c = 5.488 Å, V = 873.7 ų, Pnma, Z = 4. These dimensions and Electron backscatter diffraction (EBSD) data strongly support the structural identity between nataliakulikite and synthetic Ca₄Ti₂Fe³⁺₂O₁₁ (2CaTiO₃∙Ca₂Fe³⁺₂O₅), an intermediate compound in the system CaTiO₃-Ca₂Fe³⁺₂O₅. In general, this mineral is a Si-Fe²⁺-rich natural analog of synthetic Ca₄Ti₂Fe³⁺₂O₁₁. The X-ray powder diffraction data (CuKα -radiation), calculated from unit-cell dimensions, show the strongest lines {d [Å], (I_calc)} at: 2.681(100), 1.898(30), 2.627(26), 2.744(23), 1.894(22), 15.151(19), 1.572(14), 3.795(8). The calculated density is 4.006 g/cm³. The crystal structure of nataliakulikite has not been refined because of small sizes of grains. The Raman spectrum shows strong bands at 128, 223, 274, 562, and 790 cm⁻¹. Nataliakulikite from the Hatrurim Basin crystallized under the conditions of combustion metamorphism at high temperatures (1160–1200 °C) and low pressures (HT-region of the spurrite-merwinite facies).

Samples of Al₂O₃/MgO composite with various MgO weight contents were synthesized at high temperature in vacuum. Its phase composition, density and grain size distribution depending on the synthesis temperature and MgO quantity were studied. Composite luminesciense with electron beam excitation was registered. At the request of all authors of the paper, an updated version of this article was published on 9 October 2017. The original version supplied to AIP Publishing had an incomplete author affiliation. The affiliation did not include the name of the university. This has been corrected online.

Cooling rates of meteoritic iron–nickel alloys were estimated using a processing of morphological features of their structure. All data have been acquired with optical and scanning electron microscopy. Two types of cooling rates were obtained. Slow cooling during the formation of the meteoroid parent body determined the first type. The second type is a result of melt crystallization after a shock event.

Nanostructures were synthesized by a catalytic pyrolysis of ethanol. Air was used as a carrier gas. Both hematite nanowhiskers and multiwalled carbon nanotubes (MWCNTs) were synthesized on the Chinga surface. Several areas of the Chinga meteorite were observed, including a duplex plessite, a kamacite and its enveloping taenite rim. Hematite nanowhiskers were synthesized by a thermal oxidation of the taenite surface. MWCNTs were obtained on a kamacite and a duplex plessite surface.