History of Crystallography

The field of crystallography started with the discovery of X-rays by Röntgen who was awarded the Nobel Prize in Physics for this discovery in 1901. Max von Laue followed this by investigating the interaction of X-rays with crystals producing a diffraction pattern and he received the Nobel Prize for Physics in 1914. In 2013 it was 100 years since the pioneering work undertaken by William Henry Bragg and his son, William Lawrence Bragg, which underpins the discipline of X-ray crystallography, and for which they were jointly awarded a Nobel Prize in Physics in 1915. Building on the work by von Laue, they formulated the relationship between a crystal’s atomic structure and its X-ray diffraction pattern providing a tool which has revolutionised our understanding of the structure of matter ranging from minerals, pharmaceutical materials and catalysts to DNA, proteins and viruses.

[caption id="attachment_280" align="aligncenter" width="300"] William Henry Bragg and William Lawrence Bragg[/caption]

 

William H. Bragg held the Chair of Physics at Leeds University from 1909. Lawrence studied at Trinity College Cambridge for an undergraduate degree in Natural Sciences, graduating in 1912. It was in 1912 that Max von Laue and co-workers discovered that when X-rays were shone through a crystal of copper sulphate, the crystal acted like a grating and produced a diffraction pattern that could be measured on photographic film.

After discussing von Laue’s work with his father, Lawrence Bragg derived a formula which provides an elegant and powerful description of diffraction from crystalline materials and presented his findings at the November 1912 meeting of the Cambridge Philosophical Society. The work was published in the proceedings of the society in 1913.

The Braggs used the formula (known today as Bragg’s law) to determine the very first crystal structures from their diffraction patterns (including sodium chloride, zinc sulphide and diamond). Lawrence Bragg was only 25 when he was awarded the Nobel prize, making him the youngest ever Laureate.

There is an online copy of the 1915 textbook 'X-rays and Crystal Structures' by W. H. Bragg and W. L. Bragg.  Downloadable pamphlets on the first paper can be found here and one about the Braggs here.  You can also do a quiz about the Braggs by following this link.

The legacy of the Braggs has resulted in a family tree with many other significant scientists including a large proportion of female scientists.  One of the most famous of these is Dorothy Crowfoot Hodgkin who won a Nobel prize herself in 1964 for determining the crystal structures of biochemical molecules including penicillin and vitamin B12.  She later determined the structure of insulin.  If you want to find out more, the BBC produced an audio slideshow about the life and pioneering work of Dorothy Hodgkin

Another famous female crystallographer was Rosalind Franklin.  It was Franklin who first measured a diffraction pattern from DNA and it was this image that Watson and Crick used to determine the double helix structure of DNA.  This wasn't without controversy as Watson and Crick obtained Franklin's data without her knowledge!

 

Some high school students in the USA made an amusing youtube rap about the history of the DNA discovery and Rosalind Franklin.