Investigation of the polyhedral structure of Ga0.5In1.5Se3 by analytical methods

The crystal structure and atomic dynamics (vibrational properties) of the [Formula: see text] compound are studied at room temperature and under normal conditions. The monoclinic symmetry crystal structure of the P61 space group is explained by the polyhedral structure. The studies were carried out by the method of Raman spectroscopy. In the spectrum obtained in the frequency range [Formula: see text]–800 cm[Formula: see text], four main vibrational modes were observed: [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] cm[Formula: see text]. The analysis showed that these modes correspond to the vibration of different polyhedra. Modes [Formula: see text] and [Formula: see text] cm[Formula: see text] correspond to vibrations of bipyramids, and modes [Formula: see text] and [Formula: see text] cm[Formula: see text] correspond to vibrations of tetrahedra.

Crystal Growth of the Quasi-2D Quarternary Compound AgCrP2S6 by Chemical Vapor Transport

We report optimized crystal growth conditions for the quarternary compound AgCrP2S6 by chemical vapor transport. Compositional and structural characterization of the obtained crystals were carried out by means of energy-dispersive X-ray spectroscopy and powder X-ray diffraction. AgCrP2S6 is structurally closely related to the M2P2S6 family, which contains several compounds that are under investigation as 2D magnets. As-grown crystals exhibit a plate-like, layered morphology as well as a hexagonal habitus. AgCrP2S6 crystallizes in monoclinic symmetry in the space group P2/a (No. 13). The successful growth of large high-quality single crystals paves the way for further investigations of low dimensional magnetism and its anisotropies in the future and may further allow for the manufacturing of few-layer (or even monolayer) samples by exfoliation.

Crystal structures of [Li7(i-PrO)3(C4H10NO)3]2O and [Na(i-PrOH)2(C8H18NO2)]2

The title compounds, hexakis[μ3-2-(dimethylamino)ethanolato]hexa-μ2-isopropanolato-μ4-oxido-tetradecalithium(I), [Li7(i-PrO)3(C4H10NO)3]2O (1), and {3-[(2-methoxyethyl)(methyl)amino]-1,1-dimethylpropanolato}diisopropanolsodium(I), [Na(i-PrOH)2(C8H18NO2)] (2), were crystallized in the presence of 2-propanol (i-PrOH, C3H7OH). The structure 1 has monoclinic symmetry (C2/c) and the asymmetric unit contains half of the compound. Title compound 2 has triclinic symmetry (P\overline{1}) and the asymmetric unit is half of an inversion-symmetric aggregate. Both compounds consist of an alkali metal, an aminoalkoxide and a 2-propanol compound. Furthermore, the dimeric sodium aggregate 2 is build up by hydrogen bonding through the 2-propanol and the alkoxides. Compound 1 does not exhibit hydrogen bonding, due to the fact that the 2-propanol is deprotonated. In compound 1, benzene appeared as co-crystallate, but was suppressed by solvent masking because of strong disorder. The formula mass and density do not take account of the solvent.

Synthesis of Samarium OxysulfateSm2O2SO4 in the High-Temperature Oxidation Reaction and Its Structural, Thermal and Luminescent Properties

The oxidation process of samariumoxysulfide was studied in the temperature range of 500–1000 °C. Our DTA investigation allowed for establishing the main thermodynamic (∆Hºexp = −654.6 kJ/mol) and kinetic characteristics of the process (Ea = 244 kJ/mol, A = 2 × 1010). The enthalpy value of samarium oxysulfate (ΔHºf (Sm2O2SO4(monocl)) = −2294.0 kJ/mol) formation was calculated. The calculated process enthalpy value coincides with the value determined in the experiment. It was established that samarium oxysulfate crystallizes in the monoclinic symmetry class and its crystal structure belongs to space group C2/c with unit cell parameters a = 13.7442 (2), b = 4.20178 (4) and c = 8.16711 (8)Å, β = 107.224 (1)°, V = 450.498 (9)Å3, Z = 4. The main elements of the crystalline structure are obtained and the cation coordination environment is analyzed in detail. Vibrational spectroscopy methods confirmed the structural model adequacy. The Sm2O2SO4luminescence spectra exhibit three main bands easily assignable to the transitions from 4G5/2 state to 6H5/2, 6H7/2, and 6H9/2 multiplets.

Riesite, a New High Pressure Polymorph of TiO2 from the Ries Impact Structure

This paper describes riesite, a new high-pressure polymorph of TiO2 from the Ries impact structure, Germany. Riesite occurs in shock-induced melt veins within xenoliths of bedrock in suevite. It is structurally closely related to srilankite from which it differs by having two distinct cation sites rather than one and through its monoclinic symmetry. It is indicative that riesite forms only upon release from the shock state upon back transformation from akaogiite.

Crystal structures and biological activity of 1,1,4-triphenyl-substituted 1,3-enyne compounds

1,3-Enyne structural motifs are versatile building blocks in organic synthesis and occur widely in various natural products with many of them being highly active as cytotoxic macrolides and antitumour antibiotics. This article presents the crystal structure of three 1,1,4-triphenyl-substituted 1,3-enynes, viz. 4-(2-methylphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18 (1), 4-(2-methoxyphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18O (2), and 4-(4-nitrophenyl)-1,1-diphenylbut-1-en-3-yne, C22H15NO2 (3). The benzene ring at position 4 of the but-1-en-3-yne group bears a weakly activating methyl group in compound 1, a moderately activating methoxy group in 2 and a strongly deactivating nitro group in 3. The crystal structures of 1 and 3 both have monoclinic symmetry, while that of 2 is orthorhombic, and all of them have one molecule in the asymmetric unit. All three compounds were investigated for their antibacterial and antifungal activities. Interestingly, enyne 2 is the only compound tested that inhibited the growth of Aspergillus niger.

Structural properties of the alluaudite-type materials Ag2–xNaxMn3(VO4)3 (x=0.62 and 1.85)

The new members of the Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 2) solid solution were synthesized by a solid-state reaction route. The crystal structures of Ag1.38Na0.62Mn3(VO4)3 (x = 0.62) and Ag0.15Na1.85Mn3(VO4)3 (x = 1.85) were solved using single crystal X-ray diffraction. These phases crystallize with a monoclinic symmetry (space group C2/c), and their structures are new members of the well-known alluaudite family. In both compounds, the Ag+/Na+, Mn2+/Mn3+ and V5+ cations are eight-, six-, and four-coordinated to oxygen atoms, respectively. All the atoms are perfectly ordered except for the Ag and Na atoms which are statistically disordered over a 4b and a 4e atomic position. This single-crystal structural study confirms the existence of a full solid solution Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 1.85).