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Magnetic Susceptibility Measurements for Polycrystalline [Ni(H2O)6](ClO4)2

Rachwalska M., Tomala K.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 6

975-981

EN

The molar susceptibility of [Ni(H2O)6](ClO4)2 (powder) was investigated between 2-300Kusing superconducting quantum interference. Themagnetic moment of the sample was also measured at various magnetic strengths, until the sample became saturated. At low temperatures the sample shows an antiferromagnetic alignment. The effective magnetic moment connected with Ni2+ corresponds well with the value predicted by theory. No anomalous behavior of the molar susceptibility of [Ni(H2O)6](ClO4)2 was found at ca 225 K (as was previously stated by others authors).

2

Regularities in Complex Asymptotic Oscillations in the Belousov-Zhabotinsky Reaction at Various Residence Times and Inflow Malonic Acid Concentration

Rachwalska M., Kawczyński A.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

135-143

EN

Simple and complex oscillations have been observed in an asymptotic regime of the Belousov-Zhabotinsky (BZ) system of bromate-malonic acid-ferroin in a continuously stirred tank reactor (CSTR). Changes of the residence time and the influx concentration of malonic acid induce the appearance of regularities in complex patterns which resemble the period adding bifurcation. All experimental results can be reproduced by a simple model suggested earlier for qualitative description of asymptotic and transient oscillations observed in the BZ system.

3

Effect of temperature on manganese II-ion-catalyzed bromate-driven oscillators

Rachwalska M.

Bulletin of the Polish Academy of Sciences. Chemistry

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1998

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Vol. 46, No. 4

459-467

EN

In this paper the system: Mn2(+)-malonic acid-H2504-KBrO3 was investigated. The reaction occurred in a state far from equilibrium because a flow-through reactor was used. By measuring the platinum electrode potential and bromide ion selective electrode potential for the system studied a bifurcation diagram was obtained. Many various concentrations of reactants were used. After obtaining the bifurcation diagram, such a set of reactants' concentrations was investigated at various temperatures for which the reaction had an oscillatory character. Basing on these results it was possible to estimate the activation energy of the reaction as equal to 47.8 = 5.3 kJ/mol. It was found that under CSTR conditions Q(10) values become as low as 1.6. For two sets of initial concentrations an anomalous behavior of the oscillation period was observed. In this case the period of oscillation does not decrease when increasing the temperature but increases.