Krzysztof Skudlarski

Thermodynamics of sublimation of cadmium halides investigated by the mass-spectrometric method

Abstract The vapour pressures of cadmium chloride, bromide, and iodide were measured by the Knudsen-effusion mass spectrometry, and are expressed by the equations: ln {p( CdCl 2 )/ Pa } = −(20030+220)( K /T)+(29.22±0.34),(560 to 700 K ) , ln {p( CdBr 2 )/ Pa } = −(17110+410)( K /T)+(26.47±0.67),(560 to 670 K ) , ln {p( CdI 2 )/ Pa } = −(16770+200)( K /T)+(29.47±0.37),(460 to 590 K ) . The values of second- and third-law enthalpy and entropy of sublimation at 298.15 K have been calculated.

Mass spectrometry of the {x TlCl + (1 — xTlBr} system: determination of solid-component activities and calculation of mass spectra of gas

Abstract The mass spectrum of the vapours over the { x TlCl + (1 — x )TlBr} system has been measured over the temperature range 540–600 K. Tl + , TlCl + , TlBr + , Tl 2 + , Tl 2 Cl + and Tl 2− , Br + ions were found as well as trace amounts of Tl 2 Cl 2 + , Tl 2 Br 2 + and Tl 2 ClBr + . By measuring the ion intensity ratios, the activities over the full composition range, the excess enthalpies, the excess entropies and the excess thermodynamic potentials were determined. The activities were used for resolving the mass spectrum of the dimers and for determining the pressure equilibrium constant for the formation reaction of a mixed dimer.

Mass-spectrometric determination of excess Gibbs free energy for {(1 − x)KReO4 + xCsReO4} at 806 K

The molar excess Gibbs free energy GE and excess chemical potentials μE(KReO4) and μE(CsReO4) were determined for {(1 − x)KReO4 + xCsReO4}(s) at 806 K. The Knudsen-cell mass-spectrometric technique was used. For the empirical representations: GE = x(1−x){B1 + B2(2x−)} , μE(KReO4) = x2[B1 + B2{4(x−1)+1}] , μE(CsReO4) = (1−x)[B1(1*minus;x)− B2{1−2x)2x}] , the parameters B1 = 5.49 kJ mol−1 and B2 = − 0.43 kJ mol−1 were obtained.

Thermodynamics of the sublimation of thallium halides investigated by the mass-spectrometric method

Abstract The vapour pressures of monomeric and dimeric molecules of thallium chloride, bromide, and iodide are expressed by the equation: log 10 ( p Pa ) = −A( K T ) + B . The values of A and B are given. The values of second-law enthalpies of sublimation Δ s g H m o (298.15 K)/(kJ · mol −1 ) are: 140.8, 176.9, 136.0, 181.4, 133.1, and 174.8 for TlCl, Tl 2 Cl 2 , TlBr, Tl 2 Br 2 , TlI, and Tl 2 I 2 , respectively. The respective third-law enthalpies of sublimation Δ s g H m o (298.15 K)/(kJ · mol −1 ) are: 138.2, 172.7, 138.6, 177.1, 139.6, and 187.8.

Thermodynamics of {xCdBr2 + (1−x)CdI2}(s) investigated by mass spectrometry

The mass spectrum over {xCdBr2 + (1−x)CdI2}(s) measured at the temperature 550 K exhibits the ions Cd+, CdBr+, CdI+, CdBr2+, CdI2+, and CdBrI+. The excess molar Gibbs free energy of the solid mixture has been obtained: GEm(550 K)(J·mol−1) = x(1−x){(−306±114)+(−1404±172)(2x−1)} The mass spectrum of CdBrI(s) and the standard equilibrium constant of the reaction of formation of CdBrI(g) from 12CdBr2(g) and 12CdI2(g) at 550 K have been calculated.

Excess molar Gibbs free energy of {xTlBr+(1−x)TlI} investigated by mass spectrometry

Abstract The mass spectra of vapours over {(1− x )TlI+ x TlBr}(s) have been measured in the temperature range 540 to 580 K. Tl + , TlBr + , TlI + , Tl 2 Br + , Tl 2 I + , and Tl 2 + ions have been found. The excess molar Gibbs free energy at 560 K has been determined by measuring intensity ratios I (TlBr + )/ I (TlI + ): G m E / ( J ⋅ mo l − 1 ) = ( 1 − x ) x { 3750 + 1260 ( 2 x − 1 ) }

Mass spectrometric study of potassium cyanate and potassium cyanate - potassium cyanide system at high temperatures

Abstract Vaporization of KCNO (over the temperature range 656 - 799 K) and of KCN - KCNO system (639 - 787 K) have been investigated by the Knudsen cell - mass spectrometric technique. Enthalpies of vaporization of monomeric and dimeric molecules have been determined as 187.3 ± 4.3 kJ/mol and 210.3 ± 4.6 kJ/mol, respectively. Partial pressures over the salt have been expressed as: log p (KCNO)/Pa = - (9 781 ± 222)/ T + (11.133 ± 0.119) log p (K 2 (CNO) 2 )/Pa = - (10 983 ± 240)/ T + (11.888 ± 0.091) Appart from vaporization, decomposition of KCNO to KCN and O 2 proceeds in some extent. The KCN - KCNO melt vaporizes as KCN, KCNO, K 2 (CN) 2 , K 2 (CNO) 2 , and K 2 (CN)(CNO) molecules. The activities and vapor pressures of components have been determined over the melt composition range 0 x KCN

Resolving of the mass spectra of double salt system with the common cation

Abstract Two methods based on ionization cross section or thermodynamic activities are presented. The TlBr-Tll system is used as an example. The origin of T1 2 Br + , Tl 2 l + and Tl 2 + ions has been determined and the values of pressure equilibrium constant of mixed dimer formation reaction has been calculated.

Thermodynamic properties of {xNaCl + (1 − x)NaBr} at 840 K investigated by mass spectrometry

Abstract The excess molar Gibbs free energy of {xNaCl + (1 − x)NaBr}(s) at 840 K has been determined by Knudsen-effusion mass spectrometry: G E m (J· mol −1 ) =(1−x)x{3009+1417(2x−1)} Satisfactory agreement was found between analogous thermodynamic quantities obtained from intensities of NaCl+ and NaBr+ ions as well as from Na2Cl+ (from Na2Cl2 molecules) and Na2Br+ (from Na2Br2 molecules) ions.

Iterative resolving of mass spectra and calculation of excess thermodynamic functions of binary salt systems with common cation

Abstract The iterative method of simultaneous calculation of excess thermodynamic functions and resolving of mass spectra of mixed dimers originating from binary salt systems with common cation has been described. The results agree with those obtained by the monomer ions intensity ratios integration method.