X-ray Diffraction Data Of Compound Research Articles

PHYSICO-CHEMICAL INTERACTION IN THE Ag7PSe6 – AgSbP2Se6 SYSTEM

The study of physicochemical interaction was carried out by investigation of 12 samples within the Ag7PSe6 – AgSbP2Se6 system by DTA and XRD methods. The starting materials: Ag7PSe6 and AgSbP2Se6 were pre-synthesized from the elementary components of high purity. The thermal effects temperatures on the thermograms and X-ray diffraction data of compounds are in good agreement with the literature data. It was found that a cubic (SG P213) low-temperature modification of Ag7PSe6 and a trigonal (SG R3) modification of AgSbP2Se6, was obtained.
 A large number of effects appeared on the heating and cooling curves of the system samples, indicated that the physicochemical interaction in the Ag7PSe6 – AgSbP2Se6 system is complex. The thermograms show that the system consists of three distinct parts. X-ray diffraction results are in good agreement with DTA data. According to the results it is established:
 
 In the concentration range 100 – 44mol.% Ag7PSe6, up to the Ag4P2Se6–AgSbSe2–Se ternary system intersection the following reaction occurs:
 
 хAg7PSe6+(1-х)AgSbP2Se6=(7-7х)/5Ag4P2Se6+(1-х)AgSbSe2+(9х-4)/5Ag7PSe6+(2-2х)/5Se,
 where 0.44 ˂ x ˂ 1.00. 2.
 
 In the concentrations range 44 – 37.5 mol.% Ag7PSe6, from Ag4P2Se6–AgSbSe2–Se ternary system to Ag4P2Se6 –Sb2Se3 – Se ternary system intersections, the following reaction occurs:
 
 хAg7PSe6+(1-х) AgSbP2Se6=(2-х)/2Ag4P2Se6+(8х-3)AgSbSe2+(2-3.5х)Sb2Se3+2.5Se,
 where 0.375 ˂ x ˂ 0.44.
 
 In the concentrations range 37.5 – 0 mol.% Ag7PSe6, from the Ag4P2Se6 –Sb2Se3 – Se ternary system intersection with to AgSbP2Se6 the interaction is described by the equation:
 
 хAg7PSe6+(1-х)AgSbP2Se6=(3-8х)/3AgSbP2Se6+7х/4Ag4P2Se6+(1-х)/2Sb2Se3+(9-18х)/2Se,
 where 0˂ x ˂ 0.375.
 At the intersection points with the ternary systems the following chemical reactions take:
 4Ag7PSe6 + 5AgSbP2Se6 = 7Ag4P2Se6 + 5AgSbSe2 + 2Se
 6Ag7PSe6 + 10AgSbP2Se6 = 13Ag4P2Se6 + 5Sb2Se3 + 3Se.
 To clarify the nature of the interaction, 3 samples were additionally synthesized, with 30, 37.5, and 44.4 mol.% Ag7PSe6. The obtained samples were investigated by DTA, MSA and XRD. In the thermograms the absence of Ag7PSe6 polymorphic transformation effect and the presence of the selenium melting thermal effect were established. The study of the microstructure proved that all samples are multiphase. In the powder patterns of the sample with 30 mol.% Ag7PSe6 reflexes of Ag4P2Se6, AgSbP2Se6 and Sb2Se3 also. Diffractograms of samples with 37.5 and 44.4 mol% Ag7PSe6, which correspond to the intersection points of Ag7PSe6–AgSbP2Se6 with ternary systems Ag4P2Se6–Sb2Se3–Se and Ag4P2Se6–AgSbSe2–Se, were compared with the calculated for three-component mixtures in appropriate ratios. The calculated diffractograms are completely consistent with the experimental ones, which proves that the cross section Ag7PSe6–AgSbP2Se6 intersects Ag4P2Se6–Sb2Se3–Se and Ag4P2Se6–AgSbSe2–Se ternary, and Ag7PSe6–Ag4P2Se6–AgSbSe2–Se, Ag4P2Se6–AgSbSe2–Sb2Se3–Se, AgSbP2Se6–Ag4P2Se6–Sb2Se3–Se quaternary systems.
 Keywords: physic-chemical interaction; DTA; XRD; phase composition.

Structure and Magnetic Properties of Mixed-Ligand Complexes of 3d Metal Hexafluoroacetylacetonates with 3,5- and 3,6-Di-Tert-Butyl-O-Benzoquinones

The reaction of metal hexafluoroacetylacetonates M(hfac)2, where M = Fe, Mn, and Co, with 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) in the inert atmosphere of a dry box is found to yield mixed-ligand complexes [M(hfac)2(3,6-Q)]. When the synthesis is performed under ambient conditions or the [M(hfac)2(3,6-Q)] mother liquor is kept in air in the case of Mn(II) and Co(II), crystals of [M(hfac)2(H2O)2](3,6-Q) aqua complexes precipitate into the solid phase, in which cis-coordinated H2O molecules are hydrogen bonded to o-quinone O atoms. Single crystal X-ray diffraction data for compounds, which correlate with the results of quantum chemical calculations, show that solid [M(hfac)2(3,6-Q)] and [M(hfac)2(H2O)2](3,6-Q), where M = Co(II) and Mn(II), contain initial o-quinone molecules. In the interaction of Fe(hfac)2 with 3,6-Q, there is an intramolecular redox process during which Fe(II) is oxidized to Fe(III) and o-quinone is reduced to the respective semiquinonate radical anion, which leads to the formation of [FeIII(hfac)2(3,6-SQ)]. According to the data of magnetic measurements, a strong antiferromagnetic exchange between high-spin Fe(III) unpaired electrons and SQ provide an almost complete compensation of spin of one of the unpaired electrons of the metal ion by SQ spin. For Co a complex with 3,5-di-tert-butyl-o-benzoquinone [Co(hfac)2(3,5-Q)] is also synthesized and its structure and magnetic properties are studied. The latter prove to be similar to those of [Co(hfac)2(3,6-Q)].

Nematicidal metabolites from Gliocladium roseum YMF1.00133

A strain of the fungus Gliocladium roseum YMF1.00133 was found to secrete nematicidal metabolites against nematodes Panagrellus redivivus, Caenothabditis elegans and Bursaphelenchus xylophilus in experiments searching for nematicidal fungi. Through bioassay-guided fractionations, a unique trioxopiperazine alkaloid, gliocladin C (compound 1), and an alkylane resorcinol, 5-n-heneicosylresorcinol (compound 2) were obtained from the methanol extract of the fungus and determined by single-crystal X-ray analysis and spectroscopic data. In vitro immersion experiments showed that the ED50 values of compounds 1 and 2 after 24 h incubation were 15 and 30 μg/mL against C. elegans, 50 and 80 μg/mL against P. redivivus, and 200 and 180 μg/mL against B. xylophilus, respectively. The X-ray diffraction data of compound 1 and the nematicidal activity of compounds 1 and 2 were reported for the first time.

Crystal and Molecular Structure of 4-Nitro-2-oximino-3-phenylamino-3-thiolene-1,1-dioxide

The present publication reports the results of X-ray diffraction (XRD) analysis of 4-nitro-2-oximino-3-phenylamino-3-thiolene-1,1-dioxide crystals (I). The synthesis and the useful properties of this class of compounds are reviewed in [1]. It is noteworthy that previously [2] an X-ray structure analysis has been performed for another compound from this class, 3-methyl-4-nitro-2-oximino-3-thiolene-1,1-dioxide (II), which was assumed to exist in nitrone form. The XRD data for compound I disprove this assumption.

X-ray absorption spectroscopy study of ReO3 lattice dynamics

The lattice dynamics of ReO3 is studied for the first time by X-ray absorption spectroscopy (XAS) in the temperature range from 77 to 350 K at the rhenium L3 edge, The Debye-Waller factors are extracted for the first, fourth and sixth coordination shells of rhenium, and their temperature dependences are discussed on the basis of the Debye and Einstein vibrational models. The obtained characteristic temperatures Theta D and Theta E are compared with the ones found by other experimental techniques. The application of the Debye and Einstein models to the analysis of the XAS and X-ray diffraction data for compounds with different degrees of correlation in atomic motion is also discussed.

Complex carbonates of copper(II)

The visible absorption spectra for a copper(II) salt dissolved in (i) (NH 4) 2CO 3 and (ii) in a mixture of K 2CO 3 and KHCO 3 show absorption maxima at 650 nm for (i) and 690 and 720 nm for (ii). Methods for the preparations of (a) Na 3[Cu 2(CO 3) 3OH]. 4H 2O, (b) Rb[Cu 2(CO 3) 2(OH)]. 6H 2O, (c) K[CH 5N 3H][Cu(CO 3) 2]. H 2O, (d) K[Co(NH 3) 6] 3[Cu 2(CO 3) 4(OH)] 2 and (e) Na[Co(NH 3) 6] 3− [Cu 2(CO 3) 4(OH)] 2 are described, as well as new methods for the preparation of (f) Na 2[Cu(CO 3) 2]. 3H 2O. The (g) potassium compound, K[Cu 2(CO 3) 2(OH)], is found to be a dihydrate. Magnetic measurements for (a), (f) and (g) give values in the range 1·83-1·92 B.M. The TGA and i.r. data for the compounds are reported. The X-ray diffraction data for compounds (a) and (g) are listed.