Chemistry Nexus

by WebElements: the periodic table on the web

The positions of the elements La, Ac, Lu, and Lr in the WebElements periodic table is justified eloquently in the article by William B. Jensen.1

Abstract:1 The debate as to whether lanthanum and actinium or lutetium and lawrencium should be placed in group IIIB of the periodic table along with scandium and yttrium has along but poorly publicized history.

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December 16th, 2009

Posted In: Chemistry

The giant gypsum crystals in Mexico’s “Cueva de los Cristales” are a stunning natural wonder featuring crystals up to 11 metres long.

gypsum

These giant gypsum (hydrated calcium sulphate) crystals in the “Cave of Crystals” in the Naica mine, Chihuahua, Mexico pose an interesting problem: how are they formed. A Spanish-Mexican team led by Prof García-Ruiz et al. propose that these crystals are derived from “a self-feeding mechanism driven by a solution-mediated, anhydrite-gypsum phase transition”.

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December 15th, 2009

Posted In: Chemistry

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In honour of scientist and astronomer Nicolaus Copernicus (1473-1543), the discovering team around Professor Sigurd Hofmann suggested the name copernicium with the element symbol Cp (eventually the symbol Cn was accepted) for the new element 112, discovered at the GSI Helmholtzzentrum für Schwerionenforschung (Center for Heavy Ion Research) in Darmstadt. It was Copernicus who discovered that the Earth orbits the Sun, thus paving the way for our modern view of the world.

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December 15th, 2009

Posted In: Chemistry, Nuclear chemistry

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The complete archive of the Royal Society journals, including some of the most significant scientific papers ever published since 1665, is to be made freely available electronically for the first time until 2007.

The archive contains seminal research papers including accounts of Michael Faraday’s groundbreaking series of electrical experiments, Isaac Newton’s invention of the reflecting telescope, and the first research paper published by Stephen Hawking.The Society’s online collection, which until now only extended back to 1997, contains every paper published in the Royal Society journals from the first ever peer-reviewed scientific journal, Philosophical Transactions in 1665, to the most recent addition, Interface.

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December 15th, 2009

Posted In: Chemistry, History of chemistry

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Only carbon from the Group 14 elements forms stable double bonds with oxygen under normal conditions. When frozen, carbon dioxide is known as “dry-ice”. A non-molecular single-bonded crystalline form of carbon dioxide (phase V) exists at high pressure according to Italian and French researchers.1

Amorphous forms of silica (a-SiO2) and germane (a-GeO2) are known at ambient conditions but only recently has an amorphous, silica-like form of carbon dioxide, a-CO2.

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December 15th, 2009

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The 2006 Ig Noble prize for chemistry has been announced and was awarded to Spanish researchers Antonio Mulet, José Javier Benedito and José Bon (University of Valencia), and Carmen Rosselló (University of Illes Balears), for their outstanding research: “Ultrasonic Velocity in Cheddar Cheese as Affected by Temperature.” published in the Journal of Food Science.1

The Ig Noble prizes are administered by the publishers of the Annals of Improbable Research magazine.

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December 15th, 2009

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Abstract:
The melting behavior of Ge nanocrystals embedded within SiO2 is evaluated using in situ transmission electron microscopy. The observed melting-point hysteresis is large (±17%) and nearly symmetric about the bulk melting point. This hysteresis is modeled successfully using classical nucleation theory without the need to invoke epitaxy.1

References

1. Xu, Q., I. D. Sharp, C. W. Yuan, D.
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December 15th, 2009

Posted In: Chemistry, Materials chemistry

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A link to this article is here for historical interest. The paper is by Sir William Crookes and was published in 1914. It concerns efforts to record spectroscopic data of pure elemental silicon.1 One difficulty concerned finding a pure sample.

References

1. Crookes, W. “On the Spectrum of Elementary Silicon“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.
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December 15th, 2009

Posted In: Chemistry, Spectroscopy

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I’ve taken the liberty of reproducing a CHMED-L post from Eric Scerri about hydrogen‘s position in the periodic table.

The position of hydrogen in the periodic system is a much debated topic. Authors have suggested groups I, VII and even IV over the years. Others opt from removing H from the main body of the table, along with He. The official journal of IUPAC, called Chemistry International, has been running some articles and comments on this issue.

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December 15th, 2009

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Workers in the USA verify the production of element 114 in the reaction of 244-MeV 48Ca with 242Pu. Two chains of time- and position-correlated decays were assigned to 286114 and 287114. The observed decay modes, half-lives, and decay energies agree with the original claims of researchers at the Joint Institute for Nuclear Research at Dubna in Russia.

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December 15th, 2009

Posted In: Chemistry, Group 14 elements, Nuclear chemistry, p-Block, Radioactive elements

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