would lead to a more profound understanding of the function and properties of that
class of molecule.
This chapter recounts the early history of the development of this important
technique and describes how the early technical problems were overcome. It is a
fascinating technique because unlike the optical microscope it required the development of a deeper understanding of the way in which the X-rays interact with the
electron density in the planes of the crystal and the development of models in order
to model this electron density satisfactorily. This chapter traces how these problems
were overcome. In the early days, the structures of even simple organic molecules
would take a PhD student several months or even years to solve the structure. In time
and particularly since the 1950s, the development of more sophisticated equipment
and the massive rise in computing power made it possible to solve the threedimensional structure of an organic molecule within a few minutes with the latest
detectors on a laboratory instrument. This successful trajectory has resulted in the
ability to study ever more complex molecules and use smaller and smaller crystals.
The structures of over a million organic and organometallic compounds are now
archived in the most commonly used database, and this wealth of information creates
a new set of problems for future generations of scientists.
Keywords Bragg equation · Crystals · Databases · Diffraction · Fourier series
1 Introduction
Structure and Bonding has been published by Springer for more than 50 years, and
as its title suggests, it seeks to publish reviews associated with the structure of
chemical compounds and their interpretation using current models of chemical
bonding [1]. However, we have never published a volume devoted completely to
the most important structural technique of modern chemistry, i.e. X-ray crystallography. Paul Raithby and I decided it would be timely to publish a volume of
Structure and Bonding, which not only celebrates the great advances made in this
technique over the last 110 years but highlights issues which remain problematic. It
also seeks to identify new emerging areas which will enable the subject to continue
growing at the same rapid rate that it has achieved over the last century. This growth
has been possible by effective interdisciplinary collaborations between physicists,
chemists, biologists, mathematicians, computer programmers and engineers who
have worked together to enlarge the technical capabilities of the discipline and
provide the equations and programmes to enable the conversion of the raw data
into an accurate description of the molecule. They developed new X-ray sources
with more monochromatic and focussed beams and improved the measurements of
the diffraction spots, sped up the acquisition of data and the conversion of the data
into accurate structural information and improve the knowledge of the fundamental
2
D. M. P. Mingos
class of molecule.
This chapter recounts the early history of the development of this important
technique and describes how the early technical problems were overcome. It is a
fascinating technique because unlike the optical microscope it required the development of a deeper understanding of the way in which the X-rays interact with the
electron density in the planes of the crystal and the development of models in order
to model this electron density satisfactorily. This chapter traces how these problems
were overcome. In the early days, the structures of even simple organic molecules
would take a PhD student several months or even years to solve the structure. In time
and particularly since the 1950s, the development of more sophisticated equipment
and the massive rise in computing power made it possible to solve the threedimensional structure of an organic molecule within a few minutes with the latest
detectors on a laboratory instrument. This successful trajectory has resulted in the
ability to study ever more complex molecules and use smaller and smaller crystals.
The structures of over a million organic and organometallic compounds are now
archived in the most commonly used database, and this wealth of information creates
a new set of problems for future generations of scientists.
Keywords Bragg equation · Crystals · Databases · Diffraction · Fourier series
1 Introduction
Structure and Bonding has been published by Springer for more than 50 years, and
as its title suggests, it seeks to publish reviews associated with the structure of
chemical compounds and their interpretation using current models of chemical
bonding [1]. However, we have never published a volume devoted completely to
the most important structural technique of modern chemistry, i.e. X-ray crystallography. Paul Raithby and I decided it would be timely to publish a volume of
Structure and Bonding, which not only celebrates the great advances made in this
technique over the last 110 years but highlights issues which remain problematic. It
also seeks to identify new emerging areas which will enable the subject to continue
growing at the same rapid rate that it has achieved over the last century. This growth
has been possible by effective interdisciplinary collaborations between physicists,
chemists, biologists, mathematicians, computer programmers and engineers who
have worked together to enlarge the technical capabilities of the discipline and
provide the equations and programmes to enable the conversion of the raw data
into an accurate description of the molecule. They developed new X-ray sources
with more monochromatic and focussed beams and improved the measurements of
the diffraction spots, sped up the acquisition of data and the conversion of the data
into accurate structural information and improve the knowledge of the fundamental
2
D. M. P. Mingos