#oxidation states

[materialsscienceandengineering]

New stable form of plutonium discovered

An international team of scientists, led by the Helmholtz Zentrum Dresden-Rossendorf (HZDR), have found a new compound of plutonium with an unexpected, pentavalent oxidation state, using the ESRF, the European Synchrotron, Grenoble, France. This new phase of plutonium is solid and stable, and may be a transient phase in radioactive waste repositories. The results are published this week in Angewandte Chemie as a Very Important Paper (VIP).

Countries across the globe are making efforts to improve the safety of the nuclear waste storage in order to prevent release of radioactive nuclides to the environment. Plutonium, has been shown to be transported by groundwaters from contaminated sites for kilometres in the form of colloids, which are formed by interaction with clay, iron oxides or natural organic matter. A team of scientists lead by HZDR studies the chemistry of actinides under environmentally relevant conditions, by synthesizing such compounds, and then studying their electronic and structural behaviour both with advanced synchrotron X-ray methods experimentally as well as theoretically.

The latest paper of the international team shows how an experiment seemingly gone wrong leads to a breakthrough: the discovery of a new stable form of plutonium.

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[materialsscienceandengineering]

Supercomputing mimics berkelium experiments to validate new find

The Titan supercomputer at the Oak Ridge Leadership Computing Facility (OLCF) has enabled scientists to explore an unexpected oxidation state in the rare, radioactive element berkelium that was first observed in experiment. The OLCF is a U.S. Department of Energy (DOE) Office of Science User Facility.

An atom's oxidation state is characterized by the number of electrons it exchanges to form a compound and provides information on how an element interacts with the surrounding environment. Published in April in Nature Chemistry, the study is helping to fill in gaps in the fundamental understanding of berkelium and could have future applications for low-toxicity separation in nuclear waste management.

Scientists from Lawrence Berkeley National Laboratory (Berkeley Lab) acquired a minute sample of the most common berkelium isotope, Bk-249, from DOE's Oak Ridge National Laboratory (ORNL) through the DOE Isotope Program. Incidentally, the element and Berkeley Lab are namesakes of Berkeley, California where the element was discovered in 1949.

At ORNL, radioactive isotopes for research, including Bk-249, are produced and purified with support from the DOE Isotope Program, which recently contributed to a separate and highly publicized study—the discovery of element 117. The new element was officially named "Tennessine" thanks, in part, to ORNL's role in synthesizing the berkelium required for its creation.

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[materialsscienceandengineering]

Unexpected oxidation state for molecular plutonium discovered

Researchers at Los Alamos National Laboratory in collaboration with the University of California - Irvine (UCI) have uncovered a significant new chemical attribute of plutonium, the identification and structural verification of the +2 oxidation state in a molecular system.

"This finding marks out plutonium, already known for its extremely complex chemistry, as the actinide element with the largest number of confirmed oxidation states," said Andrew Gaunt, lead Los Alamos investigator on the project along with Stosh Kozimor.

The finding also provides a significant step towards a more complete understanding of chemical trends across the actinide series—the stuff of textbooks—and, ultimately will provide knowledge about how to manipulate and control oxidation-state chemistry and electronic structure.

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[studychemonline]

Oxidation Number – Definition, Calculation, Examples – Study Chemistry

Oxidation number of periodic table elements definition, rules, calculation, examples of redox reactions by oxidation numbers in chemistry

[bodhishadow]

Stamped Pottery Pedestal Platter, with multiple metallic glazes

John Calver, Lancashire, UK, http://www.studiopottery.co.uk/potter_profile.php?id=367

[collegeandknowledge]

Atoms in their elemental form: 0 Fluorine: -1 Hydrogen: +1 Hydrogen bonded to a metal (e.g. NaH): -1 Oxygen: -2 Oxygen in a peroxide (e.g. H2O2): -1 Alkali metals/group 1: +1 Alkaline earth metals/group 2: +2 Group 15 elements (nitrogen): +3 Group 16 elements (oxygen): -2 Group 17 elements (halogens): -1

[boatporn]

I do love me some bronze fasteners.

[collegeandknowledge]

Assigning Oxidation States

  Because about a month ago while reviewing some gen chem, I forgot how this works. Thank goodness I was an obsessive student and screencapped just about ALL of the OWL I did for chemistry in undergrad.

*Hydrogen has a +1 oxidation state when bonded to something more electronegative than carbon, a -1 oxidation state when bonded to an atom less electronegative than carbon, and an oxidation state of 0 when bonded to carbon.