Edition Peters

Edition Peters is a classical music publisher originally founded in Leipzig, Germany in 1800. The Edition Peters Group was formed in August 2010 and consists of Peters UK, Peters Germany, and Peters USA.

History

The company came into being on 1 December 1800 when the Viennese composer Franz Anton Hoffmeister (1754-1812) and the local organist Ambrosius Kühnel (1770-1813) opened a concern in Leipzig known as the "Bureau de Musique." Along with publishing, the new firm included an engraving and printing works and a retail shop for selling printed music and instruments. The first music published included chamber music works by Haydn and Mozart, plus a 14-volume collected edition of keyboard works by J. S. Bach, who had lived and worked in Leipzig from 1723-1750, but who was nearly forgotten by that time. When Hofmeister departed for Vienna in 1805, the firm had already issued several works by the then new Viennese composer, Ludwig Van Beethoven (Opp. 19-22; 39-42). Kühnel continued publishing new works, adding those of composers Daniel Gottlob Türk, Václav Tomášek, and Louis Spohr, all of whom went on to have a long relationship with the firm.

Difluoroacetylene

Difluoroacetylene, C₂F₂, is a compound of carbon and fluorine. A linear molecule, its two carbons are joined by a triple bond and have terminal fluorines: F-C≡C-F. The molecule is the perfluorocarbon analog of acetylene, C₂H₂. Preparation of difluoracetylene is difficult, with danger of explosions and with low yields. Nevertheless, the compound has been made, isolated, and characterized by NMR and IR spectroscopy. The compound is of interest as a precursor to fluoropolymers containing double bonds, analogous to polyacetylene.

Bibliography

Comet Yi–SWAN

Comet C/2009 F6 (Yi–SWAN) is a non-periodic comet which appeared in March 2009.

It was first discovered by Korean amateur astronomer Dae-am Yi on March 26, 2009, using a Canon 5D camera and 90-mm lens. It is believed to be the first comet discovered by a Korean in the modern age. Independently, on April 4 Rob Matson reported he had discovered a comet in the SWAN instrument photographs on the SOHO (Solar and Heliospheric Observatory) spacecraft website.

The comet was not bright enough to be seen by the naked eye, but was theoretically visible through amateur telescopes. However, it was harder to see than predicted, as it remained quite small and did not form much of a visible tail. It reached a peak magnitude around +8.5 in April into May, and passed 1.5 degrees south of the Double cluster in Perseus on April 23.

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Hexafluoroethane

Hexafluoroethane is a fluorocarbon counterpart to the hydrocarbon ethane. It is a non-flammable gas negligibly soluble in water and slightly soluble in alcohol.

Physical properties

Hexafluoroethane's solid phase has two polymorphs. In the scientific literature, different phase transition temperatures have been stated. The latest works assign it at 103 K (−170 °C). Below 103 K it has a slightly disordered structure, and over the transition point, it has a body centered cubic structure.

Table of densities:

Vapor density is 4.823 (air = 1), specific gravity at 21 °C is 4.773 (air = 1) and specific volume at 21 °C is 0.1748 m³/kg.

Uses

Hexafluoroethane is used as a versatile etchant in semiconductor manufacturing. It can be used for selective etching of metal silicides and oxides versus their metal substrates and also for etching of silicon dioxide over silicon. The primary aluminium and the semiconductor manufacturing industries are the major emitters of hexafluoroethane.

Together with trifluoromethane it is used in refrigerants R508A (61%) and R508B (54%).