Search results for "Moss"

New Ceramics for the Information Storage: Nanoparticles of Titanium Ferrites. Influence of Oxidation and Reduction Reactions upon the Coercivity

1997

Jarosite and hematite at Meridiani Planum from Opportunity's Mossbauer Spectrometer.

2004

Mössbauer spectra measured by the Opportunity rover revealed four mineralogical components in Meridiani Planum at Eagle crater: jarosite- and hematite-rich outcrop, hematite-rich soil, olivine-bearing basaltic soil, and a pyroxene-bearing basaltic rock (Bounce rock). Spherules, interpreted to be concretions, are hematite-rich and dispersed throughout the outcrop. Hematitic soils both within and outside Eagle crater are dominated by spherules and their fragments. Olivine-bearing basaltic soil is present throughout the region. Bounce rock is probably an impact erratic. Because jarosite is a hydroxide sulfate mineral, its presence at Meridiani Planum is mineralogical evidence for aqueous proc…

Identification of Morphological Biosignatures in Martian Analogue Field Specimens Using In Situ Planetary Instrumentation

2008

International audience; We have investigated how morphological biosignatures (i.e., features related to life) might be identified with an array of viable instruments within the framework of robotic planetary surface operations at Mars. This is the first time such an integrated lab-based study has been conducted that incorporates space-qualified instrumentation designed for combined in situ imaging, analysis, and geotechnics ( sampling). Specimens were selected on the basis of feature morphology, scale, and analogy to Mars rocks. Two types of morphological criteria were considered: potential signatures of extinct life ( fossilized microbial filaments) and of extant life (crypto-chasmoendolit…

57Fe Mössbauer spectroscopy predicts superstructure for K0.08[Cu(II)(N,N'app)Cl]2[Fe(III)(CN)6].0.92H3O.3H2O.

2007

The compound [Cu(N,N'app)Cl](2)[Fe(CN)(6)].xH(2)O, with N,N'app being bis(N,N'-3-aminopropylpiperazine), was prepared and its structure determined by single crystal X-ray analysis, confirming a ratio of two copper complexes to one iron complex; (57)Fe Mössbauer spectra showed three quadrupole doublets typical of iron(iii) low spin species which call for the presence of a superstructure.

Synthesis, characterization, crystal structures and in vitro antistaphylococcal activity of organotin(IV) derivatives with 5,7-disubstituted-1,2,4-tr…

2011

Abstract New organotin(IV) complexes of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine ( dbtp ) and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine ( dptp ) with 1:1 and/or 1:2 stoichiometry were synthesized and investigated by X-ray diffraction, FT-IR and 119 Sn Mossbauer in the solid state and by 1 H and 13 C NMR spectroscopy, in solution. Moreover, the crystal and molecular structures of Et 2 SnCl 2 (dbtp) 2 and Ph 2 SnCl 2 (EtOH) 2 (dptp) 2 are reported. The complexes contain hexacoordinated tin atoms: in Et 2 SnCl 2 (dbtp) 2 two 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine molecules coordinate classically the tin atom through N(3) atom and the coordination around the tin atom shows a …

Characterization of diorganotin(IV) complexes with captopril. The first crystallographically authenticated metal complex of this anti-hypertensive ag…

2003

Abstract Diorganotin(IV) complexes R 2 Sn(cap) (capH 2 = N -[( S )-3-mercapto-2-methylpropionyl]- l -proline; R=Me, Et, n -Bu and t -Bu) were prepared and characterised. The FTIR and Raman spectra demonstrated that the organotin(IV) moieties interact with the {S} atom of the ligand, while the other coordination sites are the carboxylate and the amide –CO groups. Mossbauer Δ data showed that the diorganotin(IV) compounds adopt slightly distorted trigonal-bipyramidal (tbp) geometry. A single-crystal X-ray study was performed on the compound Me 2 Sn(cap): the Sn atom is five-coordinated in a distorted tbp environment, with two {O} atoms in the axial positions and the {S} and two {C} atoms in t…

Spin crossover of ferric complexes with catecholate derivatives. Single-crystal X-ray structure, magnetic and Mössbauer investigations.

2005

Complexes of general formula [(TPA)Fe(R-Cat)]X·nS were synthesised with different catecholate derivatives and anions (TPA = tris(2-pyridylmethyl)amine, R-Cat2− = 4,5-(NO2)2-Cat2− denoted DNC2−; 3,4,5,6-Cl4-Cat2− denoted TCC2−; 3-OMe-Cat2−; 4-Me-Cat2− and X = BPh4−; NO3−; PF6−; ClO4−; S = solvent molecule). Their magnetic behaviours in the solid state show a general feature along the series, viz., the occurrence of a thermally-induced spin crossover process. The transition curves are continuous with transition temperatures ranging from ca. 84 to 257 K. The crystal structures of [(TPA)Fe(DNC)]X (X = PF6−; BPh4−) and [(TPA)Fe(TCC)]X·nS (X = PF6−; NO3− and n = 1, S = H2O; ClO4− and n = 1, S = H…

Structural and magnetic investigations of the mixed-valence Fe(II,III) two-dimensional layer complex, [Fe2(II) Fe2(III)(HCOO)10(C6H7N)6]n.

2004

The structure of the complex, [Fe2(II)Fe2(III)(HCOO)10(C6H7N6)n, (1) exhibits a neutral two-dimensional layer network of alternating iron(II) and iron(III) ions, bridged equatorially by formate groups. All iron atoms are octahedrally coordinated, with iron(III) coordinating axially to one gamma-picoline and one formate group, while the iron(II) centers interact axially with two gamma-picoline groups, above and below the layer plane. The complex crystallizes in the triclinic space group P1 at all studied temperatures [at 120 K, the cell dimensions are: a = 10.228(1), b = 12.071(1), c = 12.072(1) A, alpha = 89.801(2), beta = 71.149(2), gamma = 73.371(2) degrees]. An intralayer antiferromagnet…

The dynamics of (57)Fe nuclei in Fe(III)-DNA condensates.

2001

Abstract The dynamics of iron nuclei in the condensates obtained by interaction of Fe III with DNA, Fe III (DNA monomer) 2 , have been investigated by variable temperature 57 Fe Mossbauer spectroscopy. Studies were effected on gel and freeze-dried samples, obtaining nearly coincident values of the parameters isomer shift and nuclear quadrupole splitting in T ranges 20–260 K. Functions ln( A T / A 77.3 ) vs. T , here employed to investigate the dynamics of Fe nuclei, showed linear trends in the T ranges 20–150 and 150–260 K, respectively, the latter with larger slopes. Data coincided for gelled and freeze-dried specimens. No variation of δ or Δ E parameters occurred at the two T intervals, w…

The activity concentration of post-Chernobyl Cs in the area of the Opole Anomaly (southern Poland)

2015

During the years 2007 and 2010, the activity concentration of 137Cs accumulated in soil, mosses Pleurozium schreberi and lichens Hypogymnia physodes was measured. The studies covered the areas of the so-called Opole Anomaly. In consequence of the Chernobyl nuclear power plant breakdown in 1986, relatively large amounts of this radionuclide were deposited in this area. In some areas of the Anomaly, over 100 times higher surface activity of 137Cs was detected, compared to the lowest values registered in Poland. Currently, 137Cs is still present in woodlands and wastelands. As at 2 April 2013, the surface activity concentration of 137Cs in soil on the tested area was from 0.34 to 67.5 kBq m−2.…