Analytical Methodology from Lavoisier to Mendeleev

Within the period covered by Part II, 1789–1869, 37 true elements, almost all of them metals, were discovered. Prior to this time, about 14 metals had been discovered, excluding those that had been known from ancient times. The discovery of the elements during this period of interest is intimately related to the analytical methodologies available to chemists, as well as to a growing consciousness of just what an element is. Because these methods were also available to the less competent who may have lacked the skills to use them or the knowledge to interpret their results, their use also led to as many, if not more, erroneous discoveries in the same period. One can number among the major sources of error faulty interpretation of experimental data, the “rediscovery” of an already known element, sample impurities, very similar chemical properties (as in the case of the rare earths), the presence of an element in nature in very scarce or trace amounts, gross experimental errors, confusion of oxides and earths with their metals, and baseless dogmatic pronouncements by known “authorities” in the field. Antoine Laurent Lavoisier’s conceptualization of what constitutes an element was a radical break from the principles of alchemy. His stipulation that an element is a substance that cannot be further decomposed conferred an operational, pragmatic, concrete definition on what had previously been a more abstract concept. At the other end of the spectrum was the intuition of Dmitri Mendeleev who, contrary to the prevailing acceptance of Lavoisier’s concept, stressed the importance of retaining a more abstract, more fundamental sense of an element—an idea that in the long run enabled the development of the periodic table. What both men had in common is that they defined and named individual elements as those components of substances that could survive chemical change and whose presence in compounds could explain their physical and chemical properties. Mendeleev’s table has been immortalized in every chemistry classroom—and also concretely in Saint Petersburg, the city that saw most of his professional activity, by a spectacular building-sized model The analytical chemist depends on both of these concepts and indeed, analytical practice preceded Lavoisier’s concept by at least a century.

Inorganic Evolution: From Proto-Elements to Extinct Elements

Pyotr Nikolaevich Chirvinsky (1880–1955), the eminent Russian geologist, is best known as the founder of the science of meteorology. In the 1920s, Chirvinsky became the director of the Donskoi Polytechnic at Novochercassk. He spent a great deal of time as a consultant for the mines scattered throughout the Russian empire: along the Donets Basin, on the Kola and Crimean peninsulas, on the northeastern slopes of the Caucasus, and in the enormously rich mineral deposits of the Urals. His major objective in this work was to establish connections between the chemical composition of terrestrial minerals and meteorites by studying the quantity of a mineral present in a given sample of rock and the physicochemical conditions leading to its formation. He insisted that meteorites be considered legitimate objects of study in petrology, and because they had been formed in heavenly bodies and not on earth, they might provide clues regarding the formation of elements from primal material. Chirvinsky had predecessors in this way of thinking, as we shall see. The concept of prime matter is very old, coming before the definition of a chemical element, but connected to the idea of the elements. Raymond Lull (ca. 1235–1315), in his book, De Materia, defined the concept of prime matter as an element in potentia in all possible substances. The idea was very acceptable to many alchemists up until the end of the 19th century. In 1800, Jakob Joseph Winterl (1732?–1809) was a famous physician and professor at the University of Nagyszombat, in present-day Hungary. He developed a vitalistic and dualistic concept that was, from a certain point of view, anti-Enlightenment, according to which all of the chemical elements would have originated from two immaterial principles: one male, andronia, and the other female, thelyke. Although Winterl’s speculations may have been based on doubtful or misinterpreted experimental evidence, many German chemists accepted his theory. The physicist Heinrich Pfaff (1773–1852) embraced Winterl’s theory with enthusiasm, as did the pharmacist Johann Friedrich Westrumb (1751–1819) who propagated the concepts of thelyke and andronia. The first problems occurred when Winterl was unsuccessful in experimentally proving his theory.

Misadventures in Radiochemistry

Soon after the death of Pierre Curie, his widow Marie Skłodowska Curie, began to assume a prominent role in the laboratory, to which she presumably could not have aspired if her husband had survived. Within three years of her husband’s fatal accident (1906), the number of researchers in the small laboratory in Paris’ Rue Cuvier, grew from seven to 24. Marie Curie had a managerial approach to the running of the laboratory and soon increased her international prestige, gaining supremacy in the field of radioactivity. Her scientific authority was evident while Pierre was still living, but it came into prominence internationally when she criticized two claims, one substantially erroneous, of a German and of an English colleague. However, before we can pronounce on the disagreements that arose, we must look at the state of confusion that came in the wake of the discovery of radioactivity, slowly recognized by many scientists to actually be the alchemists’ transmutational dream– with a hook. Once scientists realized that one of their major articles of faith, that is, the immutability of the atom, was demolished by the radioactive decay phenomenon, they found themselves sailing on an uncharted sea. Physicists could deal with the study of rays, the measurement of energy, and the eventual necessity of measurement of half-life. But they also found that the decays gave rise to new products whose separation one from the other required the expertise of chemists. Some physicists, like Marie Curie, became expert at these separations; others came to rely on chemists to untangle the many decay sequences that would eventually lead to the key principles necessary for understanding the phenomenon. For some decades, the tried and true way of identifying and characterizing a new simple substance depended upon the determination of its atomic weight. These new substances were so fleeting and in such infinitesimally small quantities that new methods had to be invented such as electrochemical and conservation of momentum techniques. One clever method that relied on chemical similarity was the use of a so-called “carrier.”

From the Eclipse of Aldebaranium and Cassiopeium to the Priority Conflict Between Celtium and Hafnium

In 1794, Finnish scientist Johan Gadolin discovered the first of the rare earth elements in some ore deposits at Ytterby, Sweden. He called the oxide of the new element that he had isolated ytterbia and ytterbite the ore from which he had extracted it. Three years later, Anders Gustaf Ekeberg verified Gadolin’s discoveries and proposed the name of yttria (or yttric earths) for the oxide and gadolinite for the ore. For many years, chemists, among them L. N. Vauquelin, J. J. Berzelius, and M. H. Klaproth, wrestled with the problem that perhaps Gadolin’s yttrium was not a simple body but in reality contained other elements. In 1842, the Swedish chemist C. G. Mosander described how, by means of the fractional precipitations of the oxalates from dilute solutions of oxalic acid and by treatment of the hydroxides with dilute ammoniacal solutions, he seemed to have succeeded in extracting three new elements. The first was yttrium, the most basic; the second was erbium, the least basic; and the intermediate fraction he called terbium. The names terbium, erbium, and ytterbium derive from the name of the town, Ytterby. The names that Mosander gave to the three elements derived from the sequence in which they were separated: the name yttrium was not changed out of respect for Gadolin. The first element that he extracted, Mosander called terbium, and the following one he called erbium. He removed a letter from the word terbium because he had isolated it later. In the following years, it was discovered that both erbium and terbium were not single elements but mixtures of elements yet unknown. A practice developed that we might call an entente cordiale: when a discoverer split a presumed element into its constituents, one element retained the name already given by its preceding discoverer. This usage was respected by everyone, including Urbain, who, in 1907, presented his discoveries with the names neo-ytterbium and lutecium. Only Auer von Welsbach, a renowned Austrian chemist, did not respect this tacit “gentlemen’s agreement” and called the elements with atomic numbers 70 and 71 aldebaranium and cassiopeium.

The Forerunners of Celtium and Hafnium: Ostranium, Norium, Jargonium, Nigrium, Euxenium, Asium, and Oceanium

Of the naturally occurring nonradioactive elements, hafnium was the next to last to be discovered, preceding the discovery of rhenium by 3 years. It can boast of holding a very strange record: the number of claims for its discovery over the years is unequaled by any other element. This record was the cause of frustration for many scientists who, over the years, took turns in attempts to isolate it. The reason that hafnium remained undiscovered until 1922 lay not so much in that its presence in nature (long known to be quite scarce) wasn’t looked for, but in its peculiar chemical properties that bound it up intimately with zirconium. Toward the end of the 18th century, Martin Heinrich Klaproth melted some forms of yellow-green and red zirconium with sodium hydroxide and then digested the residue several times with hydrochloric and sulfuric acids to eliminate the extraneous silicon. The solution, thought to contain a number of elements, produced, upon addition of potassium carbonate, a generous precipitate. The oxide that Klaproth collected did not seem to belong to any known substance, and he called it terra zirconia. With the passing of the years, he and many other chemists, among them the renowned Jons Jacob Berzelius, determined the elemental composition of zircon and of its correlative minerals. Far from being simply ZrSiO4, zircon contained traces of iron, aluminum, nickel, cobalt, lead, bismuth, manganese, lithium, sodium, zinc, calcium, magnesium, and uranium and small amounts of the rare earths. Some impurities persistently resisted separation from zirconium oxide or zirconia and were taken erroneously for oxides of new elements (new earths). In 1825, Johann Friedrich August Breithaupt (1791–1873) reported the presence of a new element, ostranium, isolated from ostranite, a mineral similar to zircon. Twenty years later, the Swedish chemist, mineralogist, and metallurgist Lars Fredrik Svanberg (1805–78) announced the discovery of a new element. In his publication of 1845, he asserted that the zirconium oxide obtained from a variety of Siberian, Norwegian, and Indian zircon samples was in reality composed of two earths: one, zirconia, already noted, and another unknown earth.

The Beginning of a Long Series of Scientific Blunders

The Beginning of a Long Series of Scientific Blunders The enthusiasm that oft en characterizes researchers can at times distort certain preconceived convictions and deceive the scientist into believing that a controlled experiment has produced the correct result when, in fact, it is erroneous due to insufficient or incorrect data. This is the case for the discovery of a mysterious terra nobilis made by the chemist Torbern Olof Bergman. Bergman was born on March 20, 1735, in Katrineberg, Sweden. He was a chemist and mineralogist who became famous in 1775 for printing the most extensive tables of chemical affinity ever published at that time, and he was the first chemist to use letters of the alphabet as a notation system for chemical species. He took his doctorate at the University of Uppsala in 1758. After initially holding the professorship of physics and mathematics, he later took the chair in chemistry, which he retained for the rest of his life. Bergman made significant contributions to progress in quantitative analysis and metallurgy, and he developed a classification scheme of minerals based on their chemical characteristics. In 1777, Bergman confidently announced the result of an extremely expensive investigation. He studied the behavior of diamond with a blowpipe, and, aside from the presence of silicon, he seemed to have generated an unknown compound. He extracted the oxide of a metal from the diamonds, which, according to the custom of the time, he called terra nobilis. His discovery was quickly forgotten, not least because his life soon took a tragic turn. After marrying Margareta Catharina Trast in 1771, he enthusiastically continued his activities as a synthetic and analytical chemist, 3 but on July 8, 1784, at the age of only 49, he died in Medevi, Sweden. It is believed that he fell victim to poisoning from the chemical substances he used in his research. At the time of his death, he had been a member of the Royal Society of London and the Swedish Royal Academy for many years, and he was certainly one of the most famous chemists of his time.

The Obsession of Physicists with the Frontier: The Case of Ausonium and Hesperium, Littorium and Mussolinium

The attempt to find the first synthetic transuranium elements occurred via investigations completely different from anything that one could imagine. They were conducted in Rome by the renowned team of “the boys of Via Panisperna,” led by the young Enrico Fermi, affectionately called “the Pope” by his colleagues because, like the Supreme Pontiff, he was considered infallible. Nevertheless, this presumed infallibility in every area of the experimental sciences ought not stray into radiochemistry. Such hubris led to a spot on an otherwise splendid record: a clumsy interpretation of data that led to the doubtful attribution of the discovery of two transuranium elements. The hasty attempt to first name, and then retract, the two radioelements, would tarnish the prestigious and somewhat controversial figure of Enrico Fermi. On the other hand, this nonexistent discovery also sped the Roman professor to Stockholm, to receive the 1938 Nobel prize in physics. On March 25, 1934, Enrico Fermi announced the observation of neutron-induced radiation in samples of aluminum and fluorine. This brilliant experiment was the culmination of preceding discoveries: that of the neutron and that of artificial radioactivity (produced by means of α particles, deuterons, and protons). The following October, a second and crucial discovery was announced: the braking effect of hydrogenous substances on the radioactivity induced by neutrons, the first step toward the utilization of nuclear energy. The year 1934, thanks to Fermi’s research, was one of great expectations for the rebirth of Italian physics, an area that for centuries had remained in the backwater compared to the United States and the great countries of Europe. At the beginning of the 1930s, the members of Fermi’s team had explained the theory of. decay and, after 1934, with their induced radioactivity experiments, had also laid down the guidelines for research on the physics of neutrons. Rome became a reference point for nuclear research on the international level. The project of the director of the Rome Physics Institute, Senator Orso Mario Corbino (1876–1937), was nearly accomplished, a project that, from the end of the 1920s, Corbino had believed in and had not spared any expense to realize, investing all of his resources in the youthful Fermi, who was called to occupy the first chair in theoretical physics in Italy, created especially for him, when he was only 25 years of age.