J. Sarzyński

Structure and hyperfine interactions in mechanosynthesized iron–molybdenum alloys

Abstract X-ray diffraction and Mossbauer spectroscopy were used to study the structure and hyperfine interactions in Fe 80 Mo 20 and Fe 50 Mo 50 prepared by mechanical alloying. Two solid solutions, i.e. Fe(Mo) and Mo(Fe) with b.c.c. lattice were formed during milling of Fe 80 Mo 20 . Mossbauer spectra revealed different magnetic arrangements in these solid solutions. In the case of Fe 50 Mo 50 no amorphisation was observed, as literature data suggest. During mechanosynthesis of Fe 50 Mo 50 a paramagnetic Mo(Fe) solid solution was probably formed.

Spectroscopic and magnetic properties of Cu(II) complexes with selected biologically important ligands

The aim of this work was to study the spectroscopic and magnetic properties of copper(II) o-, m-, p-aminobenzoates, o-, m-, p-methoxybenzoates and o-, m- and p-nitrobenzoates. The complexes were synthesized and their compositions were evaluated by elementary analysis. The infrared and Raman spectra for Cu(II) aminobenzoates, methoxybenzoates and nitrobenzoates were recorded and assigned. The obtained data were compared with those previously published for aminobenzoic, methoxybenzoic and nitrobenzoic acids and their sodium salts. The structures of Cu(II) o-, m-, p-aminobenzoates, o-, m-, p-methoxybenzoates and o-, m- and p-nitrobenzoates as well as the change in the electronic charges distribution caused by Cu(II) complex formation were discussed.

Mössbauer and X-ray diffraction studies of mechanically alloyed Fe-Al

Powder samples of Fe25Al75 were prepared by the mechanical alloying method. Mössbauer effect, X-ray diffraction and DSC measurements indicate that Fe and Al crystalline powder transform into Fe-Al amorphous powder with increasing milling time. The X-ray diffraction patterns of the milled Fe25Al75 do not clearly show a sign of the existence of the intermetallic phases or Fe-Al solid solution. However, Mössbauer measurements reveal two sites with hyperfine magnetic fields 30.2 and 26.0 T. These sites form locally during the milling process and then they disappear.

The physico-chemical properties of 4-chlorophenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)

The complexes of 4-chlorophenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II) have been synthesized as polycrystalline solids, and characterized by elemental analysis, spectroscopy, magnetic studies and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have the following colours: pink for Co(II), green for Ni(II), blue for Cu(II) and a pale pink for Mn(II) compounds. The carboxylate group binds as monodentate and bidentate ligands. On heating to 1173K in air the complexes decompose in several steps. At first, they dehydrate in one step to anhydrous salts, that next decompose to the oxides of respective metals. Their magnetic moments were determined in the range of 76-303K. The results reveal them to be high-spin complexes of weak ligand fields.

Magnetic, thermal and spectral characterization of 2,6- dimethoxybenzoates of Co(II), Ni(II) and Cu(II)

2,4 - Dimethoxybenzoates of Mn(II), Co(II) and Cu(II) have been synthesized as hydrated or anyhydrous polycrystalline solids and characterized by elemental analysis, IR spectroscopy, magnetic studies and X-ray diffraction measurements. They possess the following colours: Mn(II) - white, Co(II) - pink and Cu(II) - blue. The carboxylate groups bind as monodentate, or a symmetrical bidentate bridging ligands and tridentate. The thermal stabilities were determined in air at 293-1173K. When heated the hydrated complexes dehydrate to from anhydous salts which are decomposed to the oxides of respective metals. The magnetic susceptibilites of the 2,4-dimethoxybenzoates were measured over the range 76-303 K and their magnetic moments were calculated. The results reveal the complexes of Mn(II), Co(II) to be high-spin complexes and that of Cu(II) to form dimer.

Physico-chemical properties of 3-methoxy-2-nitrobenzoates of some rare earth elements(III)

The complexes of 3-methoxy-2-nitrobenzoates of Pr(Ⅲ),Nd(Ⅲ),Sm(Ⅲ),Eu(Ⅲ),Gd(Ⅲ),Tb(Ⅲ),Er(Ⅲ) and Tm(Ⅲ) with the formula:Ln(CsH6NO5)3·2H2O,where Ln=lanthanides(Ⅲ),were synthesized and characterized by elemental analysis,Forier transform irtrared (FTIR) spectroscopy,magnetic and thermogravimetric studies and also by X-ray diffraction (XRD) measurements.The complexes had colours typical for Ln(Ⅲ) ions.The carboxylate groups bound as bidentate chelating.On heating to 1173 K in air they decomposed in the same way,at first,dehydrated in one step to anhydrous salts,and then decomposed to the oxides of respective metals with intermediate formation of the oxycarbonates.The enthalpy values of the dehydration process changed from 133.72 to 44.50 kJ/mol.Their solubility in water at 293 K was of the order of 10-4 mol/dm3.The magnetic moments of analysed complexes were determined by Gouys method in the range of 76-303 K.

The physico-chemical properties of 2-methoxyphenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)

The complexes of 2-methoxyhenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)with the general formula: M(C 9 H 9 O 4 ) 3 ·4H 2 O, where M(II) = Mn, Co, Ni and Cu have been synthe- sized and characterized by elemental analysis, IR spectroscopy, magnetic and thermogravi - metric studies and also X-ray diffraction measurements. The complexes have colours typical for M(II) ions (Mn(II) - a pale pink, Co(II) - pink, Ni(II) - green, and Cu(II) - blue). The carboxylate group binds as monodentate and bidentate ligands. On heating to 1273K in air the complexes decompose in the same way. At first, they dehydrate in one step to anhydrous salts, that next decompose to the oxides of respective metals with the intermediate formation of the oxycarbonates. Their solubility in water at 293K is of the order of 10 -5 mol·dm -3 . The magnetic moments of analysed complexes were determined in the range of 76-303K. The results reveal them to be high-spin complexes of weak ligand fields.

Influence of the local environment on the hyperfine interactions in Zr(Fe1-xCox)2 compounds

Ferromagnetic Laves phase compounds Zr(Fe1-xCox)2 have been investigated by means of the Mössbauer effect (57Fe) and by the time-dependent perturbed angular correlation of \gamma -rays (181Ta) technique. It has been concluded from ME experiments that by exchange of Fe by Co in the nearest neighbour shell of the nuclear probe the hyperfine magnetic field acting on 57Fe decreases by 10--12 kG.The analysis of the TDPAC experiments revealed that two different hyperfine magnetic fields: B1hf(Ta)~ 61 kG and B2hf(Ta)~ 88 kG act on the 181Ta nuclei. Both have a negative sign.

The influence of the local surrounding on the hyperfine interactions in Zr(Fe1−xNix)2 compounds

Mössbauer spectroscopy and the TDPAC method have been used to study Zr(Fe1−xNix)2 compounds forx⩽0.30. The hyperfine magnetic field at the Fe sites and the quadrupole splitting as functions of nickel concentration were analysed by use of57Fe Mössbauer spectroscopy. Values of the internal magnetic field on181Ta nuclei have been found by means of the TDPAC method.

Comparison of some properties of 2,3 - and 3,4 - dimethoxybenzoates of Cu(II), Co(II) and Nd(III)

The physicochemical properties of 2,4-, and 3,4- dimethoxybenzoates of Cu(II), Co(II) and Nd(III) were studied and compared to observe the -OCH3 substituent positions in benzene ring on the character of complexes. The analysed compounds are crystalline hydrated or anhydrous salts with colours depending on the kind of central ions: blue for Cu(II), pink for Co(II) and violet for Nd(III) complexes. The carboxylate groups bind as monodentate, bidentate bridging or chelating and even tridentate ligands. Their thermal stabilities were studied in air at 293-1173K. When heated the hydrated complexes release the water molecules and form anhydrous compounds which are then decomposed to the oxides of respective metals. Their magnetic moment values were determined in the range of 76-303K. The results reveal the compounds of Nd(III) and Co(II) to be the high-spin and that of Cu(II) forms dimer. The various positions of -OCH3 groups in benzene ring influence some of physicochemical properties of analysed compounds.