Posts Tagged ‘Bill Griffith’

The Chemistry Department at Imperial College London. A history, 1845-2000.

Friday, February 10th, 2017

The book of the title has recently appeared giving a rich and detailed view over 417 pages, four appendices and 24 pages of photographs of how a university chemistry department in the UK came into being in 1845 and its subsequent history of discoveries, Nobel prizes and much more. If you have ever wondered what goes on in an academic department, populated by and large by very bright and clever personalities and occasionally some highly eccentric ones, then go dip into this book.

Here you will learn that starting in 1845, the department had 26 enrolled students, each paying a fee to attend lectures and to do experiments in the laboratories. You may observe the changes in laboratory practices over the years, and wonder how many of those early students survived their experiences and lived into old age. The book centres around the people in the department, with many anecdotes and stories about life in such a department, some of the stories about chemistry and some not! The chemistry these people discovered and recorded in journals can be quickly accessed using the (short) DOIs provided for many of the entries in the bibliography.

Few academic departments can have been documented in such detail. Indeed one must wonder whether the wealth of written material available to the authors, Hannah Gay and Bill Griffith, during this period will be matched by the much more evanescent electronic records that have become prevalent since. Email was introduced into the department around 1987 and I suspect almost all that record has now vanished permanently. I would not envy the task of anyone faced with updating this history from 2001-2050! 

An aspect that is much harder to document is the daily routines of the undergraduate students. The book has a wealth of information about the practical laboratories and the instruments and apparatus found in the department, but a little less about the changing face of the lectures and associated written materials, the tutorials and problems classes and student’s own interactions with the professors, once the core (academic) activities and experiences of an undergraduate. Nowadays one may well find sessions on entrepreneurship instead of a problems class, or a flipped classroom replacing the lecture.

My own undergraduate stay in the department was from 1968-1971 and I might append some of those memories to this post in the future. If anyone reading this has their own evocative recollections of being a chemistry undergraduate, either at Imperial or elsewhere, can I invite you to share them here!

Lapis lazuli: the colour of ultramarine.

Saturday, March 5th, 2011

My colleague Bill Griffith has again come up with another colour challenge: that of the ancient semi-precious stone Lapis Lazuli, mined in the mountains of Afghanistan for more than 6000 years and used by painters in some medieval paintings of the Virgin, the Wilton diptych etc.

Lapis Lazuli (photo from Wikipedia).

The formula is (approximately): (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2, which sounds a bit of a challenge! But, as a very recent article points out (DOI: 10.1039/b910469k) the component that imparts the colour is the sulfur,  more specifically present in the stone as the  S3 radical anion. No recent calculation of the  UV/Vis spectrum of this simple triatomic has been reported, so here goes. A ωB97XD/aug-cc-pVQZ calculation, embedded in a continuum solvent field of water (which serves to compactify the otherwise diffuse anionic aspect) and with TD-DFT applied, shows the following (you will need an SVG enabled Web browser to see the spectrum. I am here promoting the use of this graphical standard, which differs from normal images in scaling as you resize the page size with no loss of resolution).

The λmax is ~ 650nm calculated and ~619nm measured (as a solution in an ionic liquid). Not bad agreement! The molecular orbitals involved in the excitation are shown below.

Highest doubly occupied MO. Click for 3D.

Lowest singly occupied MO. Click for 3D.

Such a precious colour, and produced using such a cheap material!