Neil Bartlett’s Mysterious Noble Gas Compound


The noble gases, also identified as uncommon or inert gases kind Group 18 of the Periodic Table, embedded among the alkali metals and the halogens. The components helium, neon, argon, krypton, xenon, and radon are the members of this group. In 1785 English physicist and chemist Henry Cavendish performed an experiment in which he passed electric sparks via an air bubble enclosed by a soap resolution (NaOH). Whilst nitrogen and oxygen were absorbed by the resolution, about 1/120th of the volume of the original bubble remained it is now recognized that the residual gas was mostly argon. Nevertheless, it was a century later before argon was finally recognized as a new element. In 1894 English physicist John William Strutt noticed that nitrogen made from air had a slightly greater density than that from nitrogen compounds.

Sir William Ramsay, collectively with Strutt, repeated the Cavendish experiment and identified argon as the unreactive species. The liquefaction of air in 1895 by Carl von Linde permitted Ramsay the additional discovery of neon, krypton, and xenon. Extraterrestrial helium had been found earlier (in 1868), based on its spectral lines in the Sun. Ramsay realized that the new elements did not match into the contemporary periodic technique of the components and recommended that they type a new group, bridging the alkali metals and the halogens. The final member of the household, radon was discovered in 1900 by Ernest Rutherford and Frederick Soddy as a decay solution of radium.

The chemical inertness of the noble gases is primarily based on their electronic structure. Each and every element has a totally filled valence shell. In fact their inertness helped to create the important idea of a steady octet. The atomic sizes of the noble gas components boost from prime to bottom in the Periodic Table, and the amount of power needed to get rid of an electron from their outermost shell, the ionization energy decreases in the very same order. Within each and every period, however, the noble gases have the largest ionization energies, reflecting their chemical inertness. Based on escalating atomic size, the electron clouds of the spherical, nonpolar, atoms grow to be increasingly polarizable, leading to stronger interactions amongst the atoms (van der Waals forces). Hence, the formation of solids and liquids is much more very easily attained for the heavier elements, as reflected in their higher melting points and boiling points. As their name implies, all members of the family are gases at area temperature and can, with the exception of helium, be liquefied at atmospheric stress.

Till 1962 only physical inclusion compounds were known. Argon, krypton, and xenon form cage or clathrate compounds with water (clathrate hydrates) and with some organics such as quinol. The host molecules are arranged in such a way that they kind cavities that can physically trap the noble gas atoms, referred to as “guests.” The noble gas will be released upon dissolution or melting of the host lattice. In 1962 the very first chemical noble gas compound, formulated as XePtF6, was synthesized by Neil Bartlett. This result spurred intense analysis activity and led to the discovery of quite a few xenon and krypton compounds. In 2000 the formation of the initial argon compound, argon fluorohydride (HArF), was reported by Leonid Khriachtchev and colleagues.

Science is frequently a collaborative discipline. But often, a single particular person, working alone in a laboratory, tends to make a stunning discovery, one particular that modifications the way scientists look at their field. One such man was Neil Bartlett, who changed the face of chemistry even though working alone in the chemistry department of the University of British Columbia. Bartlett demonstrated in 1962 that the “inertness” of the group VIII elements was a outcome of the reagents utilised in experiments, not a basic law of nature. Bartlett’s proof that the rare gases were not chemically inert meant that all existing textbooks had to be rewritten. The American chemical society and the Canadian society for chemistry designated the function of Neil Bartlett and the reactive noble gasses an international historic chemical landmark at the University of British Columbia on Could 23, 2006.

Neil Bartlett was born September 15, 1932 in Newcastle-upon-Tyne, United Kingdom. A single of his earliest, formative memories was of a laboratory experiment he conducted in a grammar college class as twelve year old. In the experiment, he mixed a resolution of aqueous ammonia (colorless) with copper sulfate (blue) in water, causing a reaction which would sooner or later create “beautiful, properly-formed crystals.” From that moment “I was hooked,” writes Bartlett, who yearned to know why the transformation took spot. He could not have known that the event would vaguely foreshadow his renowned experiment decades later in which he produced the world’s initial noble gas compound following a similarly gorgeous chemical reaction. He began to immerse himself in chemistry to the extent that he constructed his personal makeshift laboratory in his parent’s house, full with flasks and beakers and chemical substances he bought at a neighborhood supply retailer. That curiosity carried more than into academic good results and at some point earned him a scholarship for his undergraduate education.

Bartlett attended King’s College in Durham (U.K.), where he received his Bachelor of Science degree in 1954 and his doctorate in 1958. That year Bartlett was appointed a lecturer in chemistry at the University of British Columbia in Vancouver, Canada, where he remained till 1966, sooner or later reaching the rank of full professor. In 1966 he became a professor of chemistry at Princeton University whilst also serving as a member of the study employees at Bell Laboratories. In 1969, he joined the University of California, Berkeley, as a professor of chemistry, retiring in 1993. From 1969 to 1999 he also served as a scientist at the Lawrence Berkeley National Laboratory. Bartlett became a naturalized U.S. citizen in 2000.

Bartlett’s fame goes beyond the inert gas investigation to contain the general field of fluorine chemistry. He holds a particular interest in the stabilization of unusually higher oxidation states of components and applying these states to advance chemistry. Bartlett is also known for his contributions toward understanding thermodynamic, structural, and bonding considerations of chemical reactions. He helped develop novel synthetic approaches, which includes a low-temperature route to thermodynamically unstable binary fluorides, which includes NiF4 and AgF3. He found and characterized many new fluorine compounds and also produced a lot of new metallic graphite compounds, which includes some that show guarantee as powerful battery supplies.

Scientists had constantly believed that noble gases, also known as inert or rare gases, have been chemically unable to react. Helium, neon, argon, krypton, xenon, and radon (all gases at area temperature) had been viewed as the “loners” of the Periodic Table. Their inertness became a basic tenet of chemistry, published in textbooks and taught in classrooms all through the planet. Traditional scientific wisdom held that the noble gas elements could not kind compounds because their electronic structure was very stable. For all except helium, the maximum capacity of the outer electron shell of the noble gas atom is eight electrons. For helium, that limit is just two electrons. These electron arrangements are especially steady, leaving the noble gases with no a tendency to obtain or loose electrons. This led chemists to believe of them as entirely unreactive. A handful of chemists questioned the absolute inertness of the noble gases. Amongst those scientists have been Walter Kossel in 1916 and Nobel-prize winning chemist Linus Pauling in 1933. They predicted that highly reactive atoms such as fluorine may possibly form compounds with xenon, the heaviest of the noble components and whose electrons, they observed, have been not as tightly bound as those of the lighter gases.

In 1961 Neil Bartlett was teaching chemistry at the University of British Columbia in Vancouver, Canada. Some years earlier, although experimenting with fluorine and platinum, he had accidentally produced a deep-red solid whose exact chemical composition remained a mystery. With the assistance of his graduate student Derek Lohmann, he vigorously pursued the identity of the red strong. After significantly study, they at some point discovered that the recognized gaseous fluoride, platinum hexafluoride (PtF6), was able to oxidize oxygen and generate the red strong, which he and Lohmann had identified as O2+PtF6-.

What was most unusual about this compound was that it contained oxygen in the type of positively charged ions, although oxygen usually has a net adverse charge. Oxygen typically pulls electrons from other atoms and is thus known as an oxidizing agent or oxidant. But Bartlett believed that in this case, the PtF6 component was a much more strong oxidizing agent than even oxygen and was extracting electrons from oxygen, leaving oxygen with a net good charge. Even even though PtF6 was very first ready some years earlier by researchers at Argonne National Laboratory, its oxidizing power had not been recognized till Bartlett’s analysis. It was this development that led Bartlett to theorize that if PtF6 could oxidize oxygen, then it may well also be able to accomplish the “not possible” process of oxidizing xenon, whose ionization potential (power required to eliminate an electron) was really related to that of oxygen.

In March of 1962, Bartlett concocted a straightforward experiment to test his hypothesis. He set up a glass apparatus containing PtF6, a red gas in 1 container and xenon, a colorless gas in an adjoining container, separated by a seal. Here’s his recollection of the ensuing experiment, which he carried out although functioning alone in his laboratory: “Simply because my co-workers at that time (March 23, 1962) were still not sufficiently experienced to assist me with the glassblowing and the preparation and purification of PtF6 [platinum hexafluoride] necessary for the experiment, I was not ready to carry it out until about 7 p.m. on that Friday. When I broke the seal among the red PtF6 gas and the colorless xenon gas, there was an quick interaction, causing an orange-yellow strong to precipitate. At when I attempted to locate an individual with whom to share the fascinating locating, but it appeared that everybody had left for dinner!”

The reaction took spot at space temperature “in the twinkling of an eye” and was “extraordinarily exhilarating,” recalls Bartlett. He was particular that the orange-yellow solid was the world’s first noble gas compound. But convincing others would prove somewhat tough. The prevailing attitude was that no scientist could violate a single of the standard tenets of chemistry: the inertness of noble gases. Bartlett insisted that he had, to the amusement and disbelief of some of his colleagues! The proof was in the new compound he had made. That orange-yellow strong was subsequently identified in laboratory studies as xenon hexafluoroplatinate (XePtF6), the world’s 1st noble gas compound.

Within months, other chemists effectively repeated the experiment. Though the intricate chemical information behind the reaction would take years to clarify and the formula of the colorful solid was later modified as [XeF]+[PtF5]-, the significance of the experiment remained clear. Spurred by Bartlett’s good results, other scientists soon started to make new compounds from xenon and later, radon and krypton. With Bartlett’s simple experiment, the old “law” of the unreactivity of the noble gases had been vanquished. The new field of noble gas chemistry, with its exciting possibilities, had been launched.

The American Chemical Society designated the investigation of Neil Bartlett on the noble gases as an International Historic Chemical Landmark in a ceremony on Could 23, 2006 at the University of British Columbia in Vancouver. The text of the plaque on the campus of UBC reads in English and French: In this building in 1962 Neil Bartlett demonstrated the 1st reaction of a noble gas. The noble gas family of elements – helium, neon, argon, krypton, xenon, and radon – had previously been regarded as inert. By combining xenon with a platinum fluoride, Bartlett created the initial noble gas compound. This reaction began the field of noble gas chemistry, which became basic to the scientific understanding of the chemical bond. Noble gas compounds have helped generate anti-tumor agents and have been used in lasers.