Structural chemistry - where did it come from

By the beginning of the 20th century a lot was known about stmcture, but almost none of what we now call stmctural methods were available to allow scientists direct access to stractural information. The exeeption was visible spectroscopy. This provided the insight into atomic stmcture on whieh the revolutionary developments in physics of the 1920s were founded. And on those foundations rest the speetroseopic methods that we use today, as well as computational methods. 

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Noibert W. Mitzel and Carole A. Morrison. 2013 John Wiley Sons, Ltd. Published 2013 by John Wiley Sons, Ltd. 

Early representations of the structure of ethanoic acid according to (a) Kekule, (b) Scott Couper and (c) Crum Brown. 

The other structural technique that predated the rise of spectroscopic methods was mass spectrometry. The deflection of beams of ions was studied as early as 1886, but it was Francis Aston, a graduate student of J. J. Thomson, who constructed the first functioning mass spectrometer, leading to the award of a Nobel Prize in 1922. 

By the end of the 1920s much of what we now understand about quantum mechanics had been worked out. It was an astonishingly fruitful period. Almost every part of the electromagnetic spectrum has since then 

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