International Year of the Periodic Table (IYPT)
- Updated feature on the periodic table and chemical elements
- Perspective from a chemist on the Periodic Table's role in the 21st Century
The 150th Anniversary of the publication of The Principles of Chemistry by Mendeleev has been declared the International Year of the Periodic Table and is being marked by a multitude of events around the world.
Some have suggested that the Periodic Table is one of the most fruitful ideas in modern science and that it is comparable to Darwin’s theory of evolution by natural selection, proposed at approximately the same time.
There is no doubt that the Periodic Table occupies an iconic position in chemistry. In its contemporary form it is reproduced in most undergraduate inorganic textbooks and is present in almost every chemistry lecture room and classroom. Leading chemistry journals are marking this anniversary by producing editions which recount the historical development of the Periodic Table and giving an insight into some of the many alternative ways for representing it.
Structure and Bonding, as a leading book series, which publishes volumes on the relationship between chemistry and the three dimensional structures of molecules and the theories developed to understand their electronic structures is marking this important anniversary with two special volumes, which document how the Periodic Table has influenced and guided the research strategies of leading academics.
The volumes will attempt to make a unique contribution to the celebrations by documenting the alternative ways in which the Periodic Table is used by its most experienced practitioners at the beginning of the 21st Century.
Read the full editorial
The wonderful versatility of chemistry originates from the fact that every element is unique. The Periodic Table groups elements into families (Groups) which have chemical and physical characteristics which inter-relate them. Mendeleev and Lothar Meyer when they were developing the Periodic Law hoped that regular trends in the physical properties would emerge within these groups, which would enable accurate predictions to be made by linear interpolations. These aspirations proved to be over-ambitious, but nonetheless the Periodic Table has proved to be sufficiently flexible and enduring. It has incorporated the important conclusions of quantum physics in the early 20th Century and the ideas of chemical valence theory which developed the 1920s. It has also played an important role in fine tuning the properties of compounds which have found commercial uses in catalysis, electronics and as ceramics. Using the family relationships the desirable property can be optimized by systematically replacing a key element by others belonging to the same group or isoelectronic equivalents.
The Periodic Table is neither a biblical tablet of rules, nor a monolithic Rosetta stone, which provides accurate translations of chemical trends and properties. It does, however, offer a flexible two dimensional nemonic for recalling the important characteristics of the 118 known elements and the electronic structures of their constituent atoms. Specifically it provides a reliable guide to the formulae of the important compounds formed by a specific element and its general physical characteristics. It thereby provides a way of thinking for chemists which also reflects the individual’s unique history and personality - in modern parlance it provides a “fuzzy logical” framework for chemists. It is significant that the way in which the Periodic Table is used depends not only on the chemist's background, but also which part of the table is being worked on and whether the chemist is a solid state, or organometallic chemist; a spectroscopist or a theoretical chemist. So for example the way in which someone in biological chemistry uses the Periodic Table differs significantly from the way in which an organometallic chemist uses it to make compounds with unusual structures or catalytic properties. A chemist scanning the Periodic Table finds it useful because it generates a cascade of memories, smells and associations, which are both comforting and an important stimulus for the chemical imagination. For a non-chemist Oliver Sach’s “Uncle Tungsten” comes very near to accurately evoking these feelings using a sentimental but lyrical writing style.
In 1869 Dmitri Ivanovitch Mendeleev published his textbook The Principles of Chemistry and introduced the world to a classification of inorganic chemistry based on a periodic table of the elements. Although, he has been given the major credit for introducing this iconic symbol of modern chemistry its development was not the work of one individual, but the culmination of efforts by several talented individuals over a 80 year timespan. The chemical regularities associated with periodicity evolved between 1789 and 1869 and required careful experiments and imaginative contributions from Lavoisier, Dalton, Berzelius, Cannizzaro, Prout, Gmelin, Odling and Newlands. Newland’s Law of Octaves marked an important step in the evolution of the periodic system since it represented the first clear statement that the properties of the elements repeated after intervals of 8. The final leg of this marathon involved Lothar Meyer and Mendeleyev and the former actually crossed the line four years before the latter, when he published his book, but the latter was eventually rewarded with garland by the chemical community. Both suggested arranging the known elements according to their atomic weights and recognized that if a new row was started after 8 elements then vertical groups emerged with similar properties. They also realized that vacant positions in their tables were possible indicators of elements, which had not yet been discovered. Mendeleev was more definite about the criteria which were responsible for the establishing the regular patterns of elements and gave more definite predictions concerning the properties of missing elements. He was also the better publicist and for example circulated 200 printed copies of the table to the important chemical laboratories. Not all of his many predictions proved to be valid, but the discovery of scandium, gallium and germanium represented sufficient vindication of its utility and this led to his name being permanently associated with the Periodic Table. It has frequently been said that the victors write the history, but in science where enthusiasm by educators to convey as rapidly as possible the novel developments to the next generation, presentation of a clear pedagogical narrative often replaces the presentation of a completely balanced and accurate genesis of the seminal ideas.
Attention should also be drawn to the fact that the Periodic Table is not unique, and educators and enthusiasts have developed many alternative ways of representing the relationships first noted by Lothar Meyer and Mendeleev during the last 150 years. Indeed such alternative graphical representations are more numerous than the number of known elements. Some have even devised three-dimensional representations rather than the more conventional two dimensional table favoured in modern textbooks and shown on the walls of the majority of undergraduate labs and lecture theatres.
Structural differences between the d and s block elements. (Prof. D. Stalke, University of Germany).
Personal journey in through the Lanthanides and Actinides armed with the Periodic Table. (Prof. W.J. Evans, UCLA, USA).
The Chemistry of the Actinides. (Prof. D. Clark, Los Alamos National Laboratory, USA).
Mendeleev was unaware in 1869 that a whole group of monatomic and chemically unreactive gases were going to be discovered at the turn of the century and that they would play an important role in understanding the preferred valencies of the elements in the Periodic Table. This will be described in “The Important role of Noble Gas Compounds in the development of the Periodic Table” (Prof. C. Schrobilgen, McMaster University)
In the late nineteenth century there was a strong interaction between chemists and geologists which resulted in the isolation of many new elements. The geologists had the experience for identifying those seams of rock, which had workable quantities of metals, and the chemists had the expertise to separate components from the ores and concentrate them. This symbiotic relationship resulted in the discovery of many new elements which expanded Mendeleev’s table. Professor Vance of ETH Zurich examines the implications of the Periodic Table on the research activities of a modern day geologist in the chapter: “The role of the Periodic Table in geochemistry”.
Since Mendeleev’s time the important role of inorganic elements in biological processes has become apparent and therefore three chapters have been devoted to this interdisciplinary area.
A Periodic Table for Life and Medicines. (Prof. P.J. Sadler, University of Warwick, UK);
The Periodic Table’s Impact on Bio-inorganic Chemistry and biology’s selective use of metal ions. (Prof. Li Yi, University of Illinois); and
Interactions between metal ions and DNA. (Prof. C. Cardin, University of Reading, UK)
The importance of metals and particularly the transition metals in catalysis has had a major impact on our technological development over the last 150 years. The following chapters trace these developments in homogeneous and heterogeneous catalysis.
The Renaissance of 3d Metals in Homogeneous Catalysis. (Prof. S. Schneider).
The role of the Periodic Table in Heterogeneous Catalysis. (Prof. Sir John Thomas, Cambridge University, UK)
Solid state compounds and ceramics have played an important role in the development of new materials, which have commercially important electronic, magnetic and spectral properties and the following three chapters describe how the Periodic Table has played an important in the discovery of such materials and the optimization of their properties.
Synthesis and properties of zeolites guided by periodic considerations. (Prof . J.P. Pariente and Prof. G Hortigüela);
Periodic considerations and properties of layered compounds. (Prof. X. Duan and Prof. D.G. Evans); and
Periodic relationships in the perovskite family of solid state materials. (Prof. A.R. West )
The existence of the periodic table in its present form owes much from important connections between theoretical physics and chemistry. The bonding models which have emerged out of the quantum mechanical description of atoms have had important implications and are described in three chapters:
Chemical Valency: Its impact on the proposal of the Periodic Table and its Current Significance. (Prof. L. Gade, University of Heidelberg, Germany);
Periodic trends revealed by photoelectron studies of transition metal and lanthanide organometallic compounds. (Prof. J.C. Green, University of Oxford)
There will be a concluding Chapter which tries to bring together and summarise the common threads and the differences which have been highlighted in the preceding Chapters (Prof. D.M.P. Mingos, University of Oxford, UK).
In this way it is hoped to provide a forward looking guide to the way in which the Periodic Table will be used in the coming 150 years.
About the publication: Structure and Bonding
This book series uniquely bridges the journal and book format. Organized into topical volumes, the series publishes in depth and critical reviews on all topics concerning structure and bonding. With over 50 years of history, the series has developed from covering theoretical methods for simple molecules to more complex systems. Find out more
Prof D. Michael P Mingos FRS is an Emeritus Professor of Inorganic Chemistry at the University of Oxford and Series Editor of the internationally renowned review series Structure and Bonding. He was elected a Fellow of the Royal Society in 1992 and the European Academy of Sciences in 2017. He has received many prizes – the most recent was the Blaise Pascal Medal in 2017.
For more on this topic visit our International Year of the Periodic Table page