In Jingdezhen an Imperial Kiln was built in 1369 to produce porcelain that was “white as jade, thin as paper, bright as a mirror and tuneful as a bell”. It’s the colours of the glazes that caught my eye, achieved by a combination of oxidative and reductive firing in the kiln, coupled with exquisite control of the temperature.
Archive for the ‘Historical’ Category
Impressions of China 2: The colour of porcelain.
Wednesday, October 14th, 2015The chemical Web at 22 and where it might go.
Wednesday, August 19th, 2015This post is prompted by the appearance of a retrospective special issue of C&E news, with what appears to be its very own Website: internet.cenmag.org. It contains articles and interviews with many interesting people, along with several variations on the historical (albeit rather USA-centric) perspectives and a time-line covers many of the key innovations (again, from a USA-perspective). Some subjects are covered in greater depth, including computational chemistry. The periodic table too gets coverage, but surprisingly that is not of Mark Winter’s WebElements, which carries the impressive 1993-2015 continuous timeline (hence 22 in the title!).
The structure of naphthalene: 1890-1925, and a modern twist.
Saturday, July 18th, 2015This is a little historical essay into the electronic structure of naphthalene, presented as key dates (and also collects comments made which were appended to other posts).
R-X≡X-R: G. N. Lewis’ 100 year old idea.
Friday, May 22nd, 2015As I have noted elsewhere, Gilbert N. Lewis wrote a famous paper entitled “the atom and the molecule“, the centenary of which is coming up.[cite]10.1021/ja02261a002[/cite] In a short and rarely commented upon remark, he speculates about the shared electron pair structure of acetylene, R-X≡X-R (R=H, X=C). It could, he suggests, take up three forms. H-C:::C-H and two more which I show as he drew them. The first of these would now be called a bis-carbene and the second a biradical.
Fine-tuning a (hydrogen) bond into symmetry.
Friday, January 23rd, 2015Sometimes you come across a bond in chemistry that just shouts at you. This happened to me in 1989[cite]10.1039/C39890001722[/cite] with the molecule shown below. Here is its story and, 26 years later, how I responded.
Chemistry in the early 1960s: a reminiscence.
Monday, December 22nd, 2014I started chemistry with a boxed set in 1962. In those days they contained serious amounts of chemicals, but I very soon ran out of most of them. Two discoveries turned what might have been a typical discarded christmas present into a lifelong career and hobby.
Blasts from the past. A personal Web presence: 1993-1996.
Saturday, November 1st, 2014Egon Willighagen recently gave a presentation at the RSC entitled “The Web – what is the issue” where he laments how little uptake of web technologies as a “channel for communication of scientific knowledge and data” there is in chemistry after twenty years or more. It caused me to ponder what we were doing with the web twenty years ago. Our HTTP server started in August 1993, and to my knowledge very little content there has been deleted (it’s mostly now just hidden). So here are some ancient pages which whilst certainly not examples of how it should be done nowadays, give an interesting historical perspective. In truth, there is not much stuff that is older out there!
Kekulé’s vibration: A modern example of its use.
Friday, June 6th, 2014Following the discussion here of Kekulé’s suggestion of what we now call a vibrational mode (and which in fact now bears his name), I thought I might apply the concept to a recent molecule known as [2.2]paracyclophane. The idea was sparked by Steve Bachrach’s latest post, where the “zero-point” structure of the molecule has recently been clarified as having D2 symmetry.[cite]10.1002/chem.201304972[/cite]
Benzene: an oscillation or a vibration?
Wednesday, May 28th, 2014In the preceding post, a nice discussion broke out about Kekulé’s 1872 model for benzene.[cite]10.1002/jlac.18721620110[/cite] This model has become known as the oscillation hypothesis between two extreme forms of benzene (below). The discussion centered around the semantics of the term oscillation compared to vibration (a synonym or not?) and the timescale implied by each word. The original article is in german, but more significantly, obtainable only with difficulty. Thus I cannot access[cite]10.1002/jlac.18721620110[/cite] the article directly since my university does not have the appropriate “back-number” subscription.‡ So it was with delight that I tracked down an English translation in a journal that I could easily access.[cite]10.1039/JS8722500605[/cite] Here I discuss what I found (on pages 614-615, the translation does not have its own DOI).