The first crystallographically-characterised Cu(II) xanthate
Abstract The copper(II) xanthate Cu(S2COEt)2·TMEDA (1) (TMEDA = N,N-tetramethylethylenediamine) has been synthesised and is the first structurally-characterised xanthate of copper in the + 2 oxidation state. 1 has an octahedral cis, cis, cis-ligand arrangement about the metal, in which xanthate chelation is markedly asymmetric. Both bulk thermal decomposition and film growth by aerosol-assisted chemical vapour deposition (AACVD) using 1 as precursor lead to the formation of Cu2S.
Aerosol-Assisted Chemical Vapor Deposition of CdS from Xanthate Single Source Precursors
Bis-3-methylpyridine and bis-4-methylpyridine complexes of cadmium(II) ethylxanthate have been characterized by elemental analysis, NMR spectroscopy, and thermogravimetric analysis. The single crystal X-ray structures of both methylpyridine derivatives have also been determined and shown to display a cis, cis, cis-configuration of the N- and S-donor ligands. The compounds have been utilized as single source precursors to deposit CdS films on silica-coated glass substrates at 220 and 350 °C by aerosol-assisted chemical vapor deposition. The surface morphology of the films has been examined by scanning electron microscopy analysis and the crystalline phases were studied by powder X-ray diffraction. The films deposited from the 3-methylpyridine adduct comprised more densely packed and more highly crystalline hexagonal CdS than those provided by either of the other two precursors. The crystallite sizes were found to be <20 nm for films deposited from the pyridine and 4-methylpyridine adducts but to display a ...
Silica in Soils1
Publisher Summary Silica in free and combined forms is a dominant component of the solid material of many soils, and dissolved silica is commonly a major solute of soil solutions. Breakdown of primary silicates, translocation of silica in solution, and deposition of secondary silica-containing substances are involved in the development of soils. Ions essential for the growth of plants are released to the soil solution as silicates weather, and these ions may be held against leaching at exchange sites on other silicates. Silica is absorbed in appreciable quantities by some plants and is returned to the surface of the soil as the plants decay. The nature and transformations of silica and silicates in soil are, thus, fundamental to an understanding of many aspects of soil and plant sciences.