A Tale of Seven Elements, by Eric
Scerri
15 AUGUST 2013
The international hunt for chemistry’s ‘missing links’ makes for an
engrossing tale, finds Alan Rocke
In 1789, a year marked by scientific as well as political revolution, the great French chemist
Antoine Lavoisier proposed the first list of chemical elements in the modern sense. He would
lose his head in the Reign of Terror five years later, but his list of 33 “simple substances”
survived. The race for new discoveries was on: by 1860, about five dozen elements were
recognised. In 1869 Dmitri Mendeleev systematised this increasingly chaotic menagerie into
his periodic table of the elements. From then on, chemists had at least a rough idea where to
look to fill the holes in Mendeleev’s tableau.
The periodic table of the late 19th century was organised according to increasing atomic
weights, a good but (as it turned out) imperfect principle. Shortly before the Great War
erupted, a young English physicist named Henry Moseley developed an instrumental means
that could provide an unambiguous ordinal scale for the elements, soon to be called “atomic
number”. Moseley was killed in action in 1915, but others using his method quickly deduced
that there were exactly seven mysteriously “missing” elements that formed random gaps in
the table, between the lightest, hydrogen (number 1), and what was then the heaviest known,
uranium (number 92). Their modern names are protactinium, hafnium, rhenium,
technetium, francium, astatine and promethium. A highly competitive international hunt
uncovered them all over the course of the interwar period and the Second World War.
Eric Scerri offers us a fascinating account of the discovery of these seven elements. Author
of The Periodic Table: Its Story and Its Significance(2007), Scerri is superbly qualified for
this task: chemist, philosopher of science and historian, he is the foremost contemporary
analyst of the periodic table. The cast of his engrossing tale includes dozens of scientists in
many countries, avidly pursuing these last remaining prizes in the classic table of the
elements. Scerri organises the story in the most logical way, element by element. Each
chapter recounts the history of the discovery, the frequent false leads and mistaken claims,
and the personal stories of rivalry and collaboration; each concludes with a contemporary
update on the science and technological applications of the element.
There are many intriguing, surprising and often ironic commonalities in these stories. One
expected theme is the sometimes heated quarrels over legitimacy and priority of discovery; in
the hyper-nationalistic interwar period it is unsurprising that hafnium was named after
Copenhagen, rhenium after the German Rhine, and francium after – well, you know. Less
expected is the gratifying number of women in the list of protagonists: the Austrian Lise
Meitner, the German Ida Noddack, and the Frenchwomen Marie Curie, her daughter Irène
Joliot-Curie and her former student Marguerite Perey. Another surprise is the truly
astonishing number of claims of discovery subsequently shown to be erroneous. Tom Lehrer
could have a field day composing an additional verse of his song The Elements with the
mythical substances alabamium, brevium, davyum, canadium, celtium, helvetium, ilinium,
moseleyum, nipponium, pluranium and uralium.
As a professional historian of chemistry who thought that he already knew these stories,
I was surprised by how much novel and interesting material Scerri has unearthed in this
admirable book. He offers corrections to many long-standing textbook errors, both historical
and scientific, and presents a fresh, thoroughly researched understanding of a complex web
of interacting research during a period of about 30 years. It is a shame that the book is
marred by an unfortunate number of typographical and editing slips, some of them more
than trivial – the fault of Oxford University Press’ editorial production, not Scerri’s
scholarship. That said, chemists, historians and philosophers of science, as well as educated
laypeople, will unquestionably find this book an entertaining and highly instructive read.
A Tale of Seven Elements
By Eric Scerri
Oxford University Press, 200pp, £12.99
ISBN 9780195391312
Published 18 July 2013
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Review originally published as: A place at the periodic table (15 August 2013)