Rediscovery of the Elements: The Rare Earths - The Confusing Years (open access)

Rediscovery of the Elements: The Rare Earths - The Confusing Years

This article gives a timeline of research conducted on the rare earths, 17 elements found in the f-block and Group III chemical family of the Periodic Table. It covers discoveries made after the success of Swedish chemist, Carl Gustaf Mosander. The article describes the categorization of the rare earths that took place after Mosander's time, as well as separation techniques that developed.
Date: Winter 2015
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Object Type: Article
System: The UNT Digital Library
20 Mule Team (open access)

20 Mule Team

This photograph from the front cover of an issue of the Hexagon Journal displays the mock 20 mule team that stands outside of the Rio Tinto Borax Museum in Boron, California. The mule team depicts the original mode used to transport the chemical compound, borax, out of Death Valley between 1883 and 1888. A description of the photograph is shown on page 23 of the journal.
Date: Summer 2015
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Object Type: Clipping
System: The UNT Digital Library
Rediscovery of the Elements: Sir Humphry Davy and the Alkalis (open access)

Rediscovery of the Elements: Sir Humphry Davy and the Alkalis

Article provides information on the history of alkalis, particularly discoveries associated with potassium and sodium. The article also gives information on Humphry Davy, the first person to prepare alkalis in elemental form.
Date: Summer 2015
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Object Type: Article
System: The UNT Digital Library
The Reaction Kinetics of Amino Radicals with Sulfur Dioxide (open access)

The Reaction Kinetics of Amino Radicals with Sulfur Dioxide

Abstract: Application of the laser photolysis–laser-induced fluorescence method to the reaction NH2 + SO2 in argon bath gas yields pressure-dependent, third-order kinetics which may be summarized as 𝑘 = (1.49 ± 0.15) × 10^−31 (𝑇/298 K) − 0.83 cm^6 molecule^−2 s^−1 over 292 – 555 K, where the uncertainty is the 95% confidence interval and includes possible systematic errors.The quenching of vibrationally excited NH2 is consistent with a high-pressure limit for NH2 + SO2 of (1.62 ± 0.25) × 10^−11 cm^3 molecule^−1 s^−1 over the temperature range 295–505 K, where again the 95% confidence interval is shown. Abinitio analysis yields a H2N – SO2 dissociation enthalpy of 73.5 kJmol−1, and comparison with RRKM theory and the exponential down model for energy transfer yields ⟨Δ𝐸⟩down = 350 cm^−1 for Ar at room temperature.
Date: April 29, 2015
Creator: Gao, Yide; Glarborg, Peter & Marshall, Paul
Object Type: Text
System: The UNT Digital Library