请输入您要查询的字词:

 

单词 Thiele, Friedrich Karl Johannes
释义
Thiele, Friedrich Karl Johannes

Scientists
  • (1865–1918) German chemist

    Born at Ratibor (now Racibórz in Poland), Thiele studied mathematics at the University of Breslau but later turned to chemistry, receiving his doctorate from Halle in 1890. He taught at the University of Munich from 1893 to 1902, when he was appointed professor of chemistry at Strasbourg.

    In 1899 Thiele proposed the idea of partial valence to deal with a problem that had been troubling theoretical chemists for some time. The structures produced by August Kekulé in 1858 and 1865 had revolutionized chemical thought but had also produced major problems. Double bonds in chemistry usually indicate reactivity but Kekulé's proposed structure for benzene, C6H6, contained three double bonds in its ring and yet benzene is comparatively unreactive. Thus it tends to undergo substitution reactions rather than addition reactions.

    Thiele proposed that, when double and single bonds alternate, a pair of single bonds affect the intervening double bond in such a way as to give it some of the properties of a single bond. Given the ring structure of benzene, this occurs throughout the molecule and so neutralizes the activity of the double bonds. The same argument cannot be used with double bonds in a carbon chain for there the ends of the chain will be open to addition. Thiele's problem could not be completely solved until the development of quantum theory. Thiele's ideas are similar to the later concept of resonance structures – intermediate forms of molecules with bonding part way between conventional forms.


随便看

 

科学参考收录了60776条科技类词条,基本涵盖了常见科技类参考文献及英语词汇的翻译,是科学学习和研究的有利工具。

 

Copyright © 2000-2023 Sciref.net All Rights Reserved
京ICP备2021023879号 更新时间:2024/12/25 1:51:45