scholarly journals Isotopic Abundances and Atomic Weights: IUPAC Commission II.1 Today

2019 ◽  
Vol 41 (1) ◽  
pp. 24-26
Author(s):  
Juris Meija
Keyword(s):  
Periodic Table ◽  
Atomic Weight ◽  
Scientific Merit ◽  
Long Time ◽  
Isotopic Abundances ◽  
Iupac Commission

Abstract It is hard to imagine IUPAC without the Periodic Table, and in turn, without atomic weights. As IUPAC celebrates its centennial, its oldest body, the Commission on Isotopic Abundances and Atomic Weights (CIAAW) turns 120. The parent Commission was formed in March 1899 and its inaugural task was to decide the atomic weight standard: should it be based on hydrogen or oxygen? Although the issue was settled in favor of oxygen, when the CIAAW formally joined the IUPAC in 1919, the question of the atomic weight scale was back for debate suggesting that many issues before this Commission transcend their scientific merit. In fact, many view the Periodic Table and changes therein as a part of larger cultural fabric of science so any changes are likely to be debated for a long time.

scholarly journals Ten Chemical Innovations That Will Change Our World: IUPAC identifies emerging technologies in Chemistry with potential to make our planet more sustainable

2019 ◽  
Vol 41 (2) ◽  
pp. 12-17 ◽  
Author(s):  
Fernando Gomollón-Bel
Keyword(s):  
Periodic Table ◽  
Scientific Research ◽  
100Th Anniversary ◽  
Common Language ◽  
International Union ◽  
Research Education ◽  
150Th Anniversary ◽  
Global Organization ◽  
Isotopic Abundances ◽  
Iupac Commission

Abstract 2019 is a very special year in chemistry. 2019 marks two major anniversaries: the 100th anniversary of the founding of the International Union of Pure and Applied Chemistry (IUPAC), and the 150th anniversary of Dimitri Mendeleev’s first publication on the Periodic Table of Elements [1]. IUPAC is the global organization that, among many other things, established a common language for chemistry—enabling scientific research, education, and trade. In a similar manner, Mendeleev’s system classified all the elements that were known at the time, and even predicted the existence of elements that would only come to be discovered years later. These two anniversaries are closely entwined, as IUPAC has played a major role developing of the modern Periodic Table by ensuring that the most authoritative version of the table is accessible to everyone [2], establishing names and symbols for the newly discovered elements, and also constantly reviewing its accuracy through the IUPAC Commission on Isotopic Abundances and Atomic Weights.

Standard Atomic Weight of Ytterbium Revised

2015 ◽  
Vol 37 (5-6) ◽  
Keyword(s):  
Natural Resources ◽  
Life Sciences ◽  
Atomic Weight ◽  
General Assembly ◽  
Isotopic Abundances ◽  
Iupac Commission ◽  
The University

The IUPAC Commission on Isotopic Abundances and Atomic Weights (II.1) met under the chairmanship of Dr. Juris Meija, at the University of Natural Resources and Life Sciences Vienna, Austria, prior to the 48th IUPAC General Assembly in Busan, Korea, in August 2015. Following its meeting, the Commission recommended a change to the standard atomic weight of ytterbium. The IUPAC Bureau, at its meeting on 14 August, approved this change.

scholarly journals Standard Atomic Weight of Lead Revised

2021 ◽  
Vol 43 (3) ◽  
pp. 30-30
Keyword(s):  
Isotopic Composition ◽  
Atomic Weight ◽  
Atomic Mass ◽  
Lead Isotopic Composition ◽  
Technical Report ◽  
Relative Atomic Mass ◽  
Isotopic Abundances ◽  
Iupac Commission

Abstract Following the recent publication of the IUPAC Technical Report on the variation of lead isotopic composition and atomic weight in terrestrial materials [1], the IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW) is recommending changes to the standard atomic weight (i.e. relative atomic mass) of lead:

The Seven Last Infra-Uranium Elements to Be Discovered

2019 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Periodic Table ◽  
Atomic Weight ◽  
Weak Acid ◽  
Ray Method ◽  
Natural Sources ◽  
Transuranium Elements ◽  
X Ray ◽  
Naturally Occurring ◽  
Missing Element

The term “infra-uranium,” meaning before uranium, is one that I have proposed by contrast to the better-known term transuranium elements that are discussed in the following chapter. The present chapter concerns the last seven elements that formed the missing gaps in the old periodic table that ended with the element uranium. After Moseley developed his X-ray method, it became clear that there were just seven elements yet to be isolated among the 92 naturally occurring elements or hydrogen (#1) to uranium (#92). This apparent simplicity is somewhat spoiled by the fact that, as it turned out, some of these seven elements were first isolated from natural sources following their being artificially created, but this raises more issues that are best left to the next chapter of this book. The fact remains that five of these seven elements are radioactive, the two exceptions being hafnium and rhenium, the second and third of them to be isolated. The first of the seven final infra-uranium elements to be discovered was protactinium, and it was one of the lesser-known predictions made by Mendeleev. In his famous 1896 paper, Mendeleev indicated incorrect values for both thorium (118) and uranium (116). (See figure 1.6.) A couple of years later, he corrected both of these values and showed a missing element between thorium and uranium (figure 4.4). In doing so, Mendeleev added the following paragraph, in which he made some specific predictions. . . . Between thorium and uranium in this series we can further expect an element with an atomic weight of about 235. This element should form a highest oxide R2O5, like Nb and Ta to which it should be analogous. Perhaps in the minerals which contain these elements a certain amount of weak acid formed from this metal will also be found.. . . The modern atomic weight for eka-tantalum or protactinium is 229.2. The apparent inaccuracy in Mendeleev’s prediction is not too surprising, however, since he never knew that protactinium is a member of only four “pair reversals” in the entire periodic table.

Isotope-abundance variations of selected elements (IUPAC Technical Report)

2002 ◽  
Vol 74 (10) ◽  
pp. 1987-2017 ◽  
Author(s):  
Tyler B. Coplen ◽  
John Karl Böhlke ◽  
P. De Bièvre ◽  
T. Ding ◽  
N. E. Holden ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Radioactive Decay ◽  
Atomic Weight ◽  
Chemical Fractionation ◽  
Isotope Abundance ◽  
Isotopic Compositions ◽  
Technical Report ◽  
Isotopic Abundances ◽  
Calcium Iron ◽  
Physical And Chemical

Documented variations in the isotopic compositions of some chemical elements are responsible for expanded uncertainties in the standard atomic weights published by the Commission on Atomic Weights and Isotopic Abundances of the International Union of Pure and Applied Chemistry. This report summarizes reported variations in the isotopic compositions of 20 elements that are due to physical and chemical fractionation processes (not due to radioactive decay) and their effects on the standard atomic-weight uncertainties. For 11 of those elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine, copper, and selenium), standard atomic-weight uncertainties have been assigned values that are substantially larger than analytical uncertainties because of common isotope-abundance variations in materials of natural terrestrial origin. For 2 elements (chromium and thallium), recently reported isotope-abundance variations potentially are large enough to result in future expansion of their atomic-weight uncertainties. For 7 elements (magnesium, calcium, iron, zinc, molybdenum, palladium, and tellurium), documented isotope variations in materials of natural ter- restrial origin are too small to have a significant effect on their standard atomic-weight uncertainties. This compilation indicates the extent to which the atomic weight of an element in a given material may differ from the standard atomic weight of the element. For most elements given above, data are graphically illustrated by a diagram in which the materials are specified in the ordinate and the compositional ranges are plotted along the abscissa in scales of (1) atomic weight, (2) mole fraction of a selected isotope, and (3) delta value of a selected isotope ratio.

scholarly journals Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)

2018 ◽  
Vol 90 (2) ◽  
pp. 395-424 ◽  
Author(s):  
Antonio Possolo ◽  
Adriaan M. H. van der Veen ◽  
Juris Meija ◽  
D. Brynn Hibbert
Keyword(s):  
Probability Distribution ◽  
Isotopic Composition ◽  
Probability Distributions ◽  
Atomic Weight ◽  
Relative Molecular Mass ◽  
Detailed Knowledge ◽  
Technical Report ◽  
Other Information ◽  
Isotopic Abundances ◽  
Molecular Masses

AbstractIn 2009, the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) introduced the interval notation to express the standard atomic weights of elements whose isotopic composition varies significantly in nature. However, it has become apparent that additional guidance would be helpful on how representative values should be derived from these intervals, and on how the associated uncertainty should be characterized and propagated to cognate quantities, such as relative molecular masses. The assignment of suitable probability distributions to the atomic weight intervals is consistent with the CIAAW’s goal of emphasizing the variability of the atomic weight values in nature. These distributions, however, are not intended to reflect the natural variability of the abundances of the different isotopes in the earth’s crust or in any other environment. Rather, they convey states of knowledge about the elemental composition of “normal” materials generally, or about specific classes of such materials. In the absence of detailed knowledge about the isotopic composition of a material, or when such details may safely be ignored, the probability distribution assigned to the standard atomic weight intervals may be taken as rectangular (or, uniform). This modeling choice is a reasonable and convenient default choice when a representative value of the atomic weight, and associated uncertainty, are needed in calculations involving atomic and relative molecular masses. When information about the provenance of the material, or other information about the isotopic composition needs to be taken into account, then this distribution may be non-uniform. We present several examples of how the probability distribution of an atomic weight or relative molecular mass may be characterized, and also how it may be used to evaluate the associated uncertainty.

scholarly journals Isotopic Abundances and Atomic Weights: History of IUPAC Commission II.1 in the ­Service of Chemistry

2019 ◽  
Vol 41 (1) ◽  
pp. 21-23
Author(s):  
John R. De Laeter
Keyword(s):  
Fundamental Importance ◽  
Science Technology ◽  
History Of ◽  
Isotopic Abundances ◽  
Iupac Commission

Abstract Atomic weights are of fundamental importance in science, technology, trade and commerce. In particular, atomic weights relate mass to molar quantities. It is therefore not surprising that the measurement of atomic weights has played a central role in the development of chemistry and continues to be a key component in the progress of discipline.

scholarly journals The critical constants and orthobaric densities of xenon

1912 ◽  
Vol 86 (591) ◽  
pp. 579-590 ◽  
Keyword(s):  
Equation Of State ◽  
Boiling Point ◽  
Periodic Table ◽  
Atomic Weight ◽  
Atomic Volume ◽  
Liquid Xenon ◽  
Rare Gases ◽  
Critical Constants

Rudorf, in a paper on the rare gases and the equation of state, has drawn attention to the high value found by Ramsay and Travers for the density of liquid xenon at its boiling point. As is well known the atomic volume in any group of elements in the periodic table either increases regularly with rise of atomic weight or remains approximately constant, so that it is to be expected that the atomic volume of xenon would be greater than of krypton, since the value for krypton exceeds that of argon. If Rudorf's calculated value for the density of neon is taken into account, this anomaly becomes more striking, as is shown from the following table taken from his paper:-

Reliable solubility data in the age of computerized chemistry. Why, how, and when?

2001 ◽  
Vol 73 (5) ◽  
pp. 825-829 ◽  
Author(s):  
John Rumble ◽  
Angela Y. Lee ◽  
Dorothy Blakeslee ◽  
Shari Young
Keyword(s):  
Reference Data ◽  
Driving Forces ◽  
Solubility Data ◽  
International Union ◽  
Time Period ◽  
Property Data ◽  
The World ◽  
Long Time ◽  
Iupac Commission ◽  
Physical And Chemical

Since 1979, the International Union of Pure and Applied Chemistry (IUPAC) Commission V.8 on Solubility Data has published over 70 compilations of evaluated data on the solubility of gases in liquids, liquids in liquids, and solids in liquids. These volumes represent one of the largest collections of chemical property data ever produced and are the result of work of scientists throughout the world. In 1998, IUPAC signed an agreement with the National Institute of Standards and Technology (NIST) to continue the series by replacing the monographs by articles in the Journal of Physical and Chemical Reference Data. Five data compilations have already been published in the Journal, and many more are under way. Recently, IUPAC and NIST have concluded another agreement about computerizing all previously published IUPAC solubility data. In this paper, we describe in detail the computerization of IUPAC solubility data, with some emphasis on harmonizing data published over a long time period. We describe the anticipated query paths that will be supported. We also discuss some of the driving forces for making these and other data resources available over the World Wide Web.

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