Matjaž Kristl

Sonochemical synthesis of nanocrystalline mercury sulfide, selenide and telluride in aqueous solutions

Nanocrystalline mercury chalcogenides HgE (E=S, Se, Te) were synthesized in a single step by a convenient, simple sonochemical method. Mercury nitrate, Hg(NO3)2, dissolved in 0.1 M ethylenediamine tetraacetic acid (EDTA), was used as the source of mercury and elemental chalcogenes, dissolved in a NaOH solution, as the sources of chalcogenide. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDAX). The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the complexing agent EDTA plays a crucial role in the process.

A sonochemical method for the preparation of cadmium sulfide and cadmium selenide nanoparticles in aqueous solutions.

Sonochemistry is a branch of chemistry where sound energy in the form of ultrasound is used to influence the course of reactions. A short-term, local increase in temperature occurs when the solutions and suspensions are irradiated by ultrasound. This happens because the substance absorbs the ultrasound waves. The purpose of this research was the synthesis of CdS and CdSe nanoparticles. We used cadmium sulfate hydrate (CdSO(4).8/3H(2)O), elemental S and Se. Aqueous solutions of NaOH, Na(2)SO(3) and EDTA were used as the solvents. During the syntheses, we used a direct immersion ultrasound probe by vibracell. The device operates with a constant frequency of 20 kHz, with the possibility to change the amplitude and with it the input of energy to the time unit. The products were characterized by X-ray powder diffraction (XRD), thermal analyses (TGA, SDTA) and TEM analyses.

Preparation and Study of Zinc Ferrite Nanoparticles with a High Magnetization

The zinc-doped maghemite nanoparticles were prepared using ultrasonic radiation. As a precursor, a suspension of maghemite in an alkaline aqueous solution of zinc nitrate at pH = 9 was sonicated. They were investigated by x-ray diffraction, Mössbauer spectroscopy, high-resolution electron microscopy (HREM), and superconducting quantum interference device (SQUID) magnetometry. The results show that by using ultrasound radiation, zinc Zn2+ can substitute for Fe3+ up to a composition close to zinc ferrite (ZnFe2O4), which has a random distribution of Fe3+ ions over both A and B sublattices in the spinel structure with an inversity parameter of δ = 0.322. This leads to a maximum saturation magnetization (M s ) of 64.1 emu/g at 300 K and 73.5 emu/g at 2 K.

Preparation of Nanosized Copper and Cadmium Chalcogenides by Mechanochemical Synthesis

Nanosized copper and cadmium chalcogenides have been synthesized by mechanochemical route from elementary precursors, using a SPEX 8000M ball mill. Most reactions were carried out in air, while some of the reactions had to be performed under nitrogen to avoid oxidation. The obtained nanoparticles were characterized by X-ray powder diffraction (powder XRD) and transmission electron microscopy (TEM). Following products were obtained and characterized: CuS, CuSe2, Cu7Te5, CdS, CdSe, and CdTe, with particle sizes within 8 and 19 nm.

Kristallstruktur und thermische Analyse von Hydroxylammonium-hexafluorotitanat(IV)-dihydrat und Hydroxylammonium-hexafluoroindat(III)

Summary. Crystals of (NH3OH)2TiF6ċ2H2O have been isolated. The compound crystallizes in the monoclinic system (P21/c, No. 15) with cell parameters of a=6.203(1) Å, b=10.057(1) Å, c=7.464(1) Å, and β=110.653(6)°. Reactions in the system In (OH)3– NH3OHF – HF have been investigated. Crystals of (NH3OH)3InF6 were isolated from aqueous solution. The compound crystallizes in the trigonal system (R3c) with a=b=c=7.764(2) Å, α=β=γ=97.21(4)°. The thermal decomposition of both compounds was studied by TG and DSC analysis; the decomposition products were characterized by X-ray powder diffraction.

Beitrag zur Synthese des Hydroxylammoniumfluorids

SummaryHydroxylammonium fluoride was prepared in aqueous solution by the reaction of hydroxylamine with aqueous hydrogen fluoride. The solubility in water (148.7 g/100 g) and ethanol (0.146 g/100 g), the density (1.621±0.005 g/cm3) and the metling point (97.8±2 °C) of the compound have been determined. [NH3OH]F crystallizes orthorombic, Pabc,a=6.490(1) Å,b=9.799(1) Å,c=13.519(2) Å.

Synthesis of nickel and cobalt sulfide nanoparticles using a low cost sonochemical method

Nickel and cobalt sulfides are promising materials in different cutting-edge research areas like solar cells, supercapacitors, catalysts, and electrode materials. Nickel and cobalt sulfides with various stoichiometries have been synthesized sonochemically from Ni(CH3COO)2 ∙ 4H2O, Co(CH3COO)2 ∙ 2H2O and different sulfur precursors using a direct immersion ultrasonic probe. The products were characterized by X-ray powder diffraction, transmission electron microscopy (TEM) including EDX analysis, IR and UV–Vis spectroscopy and elemental analysis. Following products have been obtained: NiS, Ni3S4, CoS1.097 and Co9S8, with average crystallite sizes in the range 7−30 nm. Effects of different reaction conditions on the size, morphology and optical band-gap energy were evaluated. Optical band-gap energies in the range 3.3 eV−3.8 eV were observed for the obtained nanoparticles.

The synthesis, structure and physical properties of lanthanide(III) complexes with nicotinic acid

AbstractThis article reports the synthesis of novel, rare-earth coordination complexes with nicotinic acid. Three compounds with the general formula Ln2[(C5H4NCOO)6(H2O)4] (Ln = Yb, 1; Ln = Gd, 2; Ln = Nd, 3) were prepared from relatively cheap and readily available reactants. Their compositions and structure were characterized by IR spectroscopy and single-crystal X-ray diffraction. The magnetic and thermogravimetric properties were also studied. The complexes consist of centrosymetric, dimeric molecules having all six nicotinato ligands coordinated with the central atom in the bidentate mode. The coordination environment of the Ln3+ for all three compounds is 8. Here we describe the crystal structure of Yb and Gd complexes with nicotinic acid.

Untersuchungen des Hydroxylammonium-Fluorogallats

SummaryCrystals of (NH3OH)3GaF6 have been isolated from aqueous solution. The compound crystallizes triclinic, with cell parametersa=6.539(5) Å,b=6.924(5) Å,c=9.403(1) Å, α=87.01(9)°, β=83.98(8)°, γ=70.28(8)°. The thermal decomposition was studied by TG and DSC analysis.

Syntheses of Ferrite Nanoparticles Using Ultrasound Irradiation

Sonochemically assisted co-precipitation has been used to prepare nanosized manganesezinc- ferrite powder. A suspension of constituent hydroxides was ultrasonically irradiated for various times with high-intensity ultrasound radiation (20 kHz, 750 W) using a direct-immersion titanium horn. The average grain size and magnetization of the synthesized MnZn-ferrite nanoparticles gradually increases with the time of ultrasonic irradiation.