Atomic weights of the elements 2009 (IUPAC Technical Report)

Abstract

Abstract:The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of 11 elements. Many atomic weights are not constants of nature, but depend upon the physical, chemical, and nuclear history of the material. The standard atomic weights of 10 elements having two or more stable isotopes have been changed to reflect this variability of atomic-weight values in natural terrestrial materials. To emphasize the fact that these standard atomic weights are not constants of nature, each atomic-weight value is expressed as an interval. The interval is used together with the symbol [a; b] to denote the set of atomic-weight values, A r (E), of element E in normal materials for which a ≤ A r (E) ≤ b. [204.382; 204.385] from 204.3833(2). This fundamental change in the presentation of the atomic weights represents an important advance in our knowledge of the natural world and underscores the significance and contributions of chemistry to the wellbeing of humankind in the International Year of Chemistry 2011. The standard atomic weight of germanium, A r (Ge), was also changed to 72.63(1) from 72.64(1).

Development of High Purity Dibutyl Sulfide Certified Reference Material (NMIJ CRM 4221-a) for Determination of Sulfur in Fuels

“…Judging from the GC-SCD measurement, sulfur is included in impurity 1. The ratio of the MS spectral intensity of possible molecular ion, m/z 146 to that of m/z 148, was 20 to 1, which is close to the isotope abundance ratio of 32 S to 34 S, 94.99 to 4.25 6) . Therefore, impurity 1 was identified as an isomer of dibutyl sulfide (molecular weight, 146) containing one sulfur atom per molecule.…”

“…Since the freezing point depression method is a primary method of the measurement and was validated by a mass balance method, the obtained purity is traceable to the SI 5) . In addition, the calculated molecular weight of the compounds and the atomic weight of sulfur were based on the IUPAC atomic weight table (2009) 6) . Therefore, the certified value calculated from the above parameters is traceable to the SI.…”

Separation of ultrafast spin currents and spin-flip scattering in Co/Cu(001) driven by femtosecond laser excitation employing the complex magneto-optical Kerr effect

“…It was calculated with n hot /dt = G(t) − n hot /τ therm and dn therm /dt = n hot /τ therm , where n hot (t) and n therm (t) are factors between 0 < n < 1, G(t) is a normalized Gaussian function with a FWHM of 35 fs and τ therm = 150 fs is the thermalization time of the electronic system, which is a typical time for a 3d metal [26]. The used parameters are the electron-phonon coupling constants g Co = 9.3 · 10 7 W/m 3 · K, g Cu = 10 7 W/m 3 · K [27], the electronic heat capacity coefficients γ Co = 4.4 mJ/mol · K 2 , γ Cu = 0.69 mJ/mol·K 2 [28], the specific heats for T → ∞ C Co = 24.81 J/mol· K, C Cu = 24.43 J/mol · K, the Debye temperatures Θ Co = 386 K, Θ Cu = 310 K [29], the mass densities ρ Co = 8.86 g/cm 3 , ρ Cu = 8.96 g/cm 3 [31], the molar masses M Co = 58.93 g/mol, M Cu = 63.55 g/mol [32], the thermal conductivities κ Co = 100 W/m · K, κ Cu = 400 W/m · K [29], the Curie temperature of Co T C = 1388 K [33], and the M3TM scaling factor for the demagnetization rate of Co R = 25.3 ps −1 [17].…”

Evidence of nanostructuration from the heat capacities of the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid series

“…15 26 The relative atomic masses of the 11 elements have been presented as an interval, in the latest IUPAC technical report 2009. 27 Since the values reported in the IUPAC Commission in 2007 28 are within the presented interval, we choose to use the relative atomic masses recommended by the IUPAC report 2007 in this work. 28 All the uncertainties are given as twice of the standard deviation of the mean, and include the calibration uncertainty.…”