Analysis of interlaboratory measurements on the vapor pressure of gold

Abstract

Abstract

High-temperature mass spectrometry: Instrumental techniques, ionization cross-sections, pressure measurements, and thermodynamic data (IUPAC Technical Report)

“…Otherwise, lower accuracy may result as in any weight-loss procedure. This issue is illustrated by interlaboratory comparison of the Au vapor pressure [209] by conventional as well as by MS techniques: the estimated total uncertainty for each set of experiments in a single laboratory was δp/p = 55 % and the overall weighted average error from the accepted measurements, 10 %.…”

“…The standard deviation is, hence, known for the thermodynamic quantities ∆ r H and ∆ r S derived from equilibrium constants measured in some temperature interval. Statistical formulae for computing the standard deviations by use of the curvature matrix are presented in "Analysis of Interlaboratory Measurements on the Vapor Pressure of Gold" [209]. They are reproduced here to illustrate the treatment that provides error estimates in the Second Law analysis of the Clausius-Clapeyron equation, in the form ln K p = A + BX with X = 1/T, A = ∆ r S /RT, and B = -∆ r H /R, viz.…”

A mass spectrometric study of the vaporization of boron phosphate (BPO4)

“…In this case, the P 3 O 7 and P 4 O 10 ions are not observed in the mass spectrum, the AE of the PO ion decreases down to 8.9 eV and the relative intensity of the BPO 3 ion, with the AE of 12.2 eV increases. All these facts indicate that, when molybdenum cells are used, boron phosphate reacts with the cell material; in doing so, PO 2 and BPO 4 are partially reduced with respect to PO and BPO 3 .…”

“…The temperature was measured by an optical pyrometer. Testing the instrument was conducted by measuring the vapor pressures of the reference substances: calcium fluoride 6 from the platinum cells and silver metal 7 from the molybdenum cells. The appearance energies (AE) of ions were measured by the vanishing current method with Ag as a potential standard, which was found to be accurate to within AE0.3 eV.…”

A Knudsen Effusion High Temperature Assembly for a Quadrupole QMG-420 Mass Spectrometer

“…Silver and caesium chloride are the standard substances recommended by IUPAC (Division of Inorganic Chemistry Commission on High Temperatures and Refractory Materials) for measuring partial pressures of vapour and enthalpies of sublimation of low volatility substances. 3,[7][8][9] The thermodynamic functions of magnesium, studied as an example of a low volatility metal, were compared with the reference values. 10 In the mass spectra of the vapour over CsCl, Ag and Mg at an ionization energy of 70 eV the following ions were identified: Cs + , CsCl + , CsCl 2 + over caesium chloride in the temperature range 770-880 K; Ag + over silver in the temperature range 1200-1550 K; Mg + over magnesium in the temperature range 660-800 K. This is in agreement with the information on the ionization processes during vaporization of CsCl, Ag and Mg, 3 when the corresponding vapour species over them were identified as CsCl and (CsCl) 2 , Ag and Mg.…”