MACLEAN'S REPORTS

SCIENCE

How Neil Bartlett broke an old law and won his place in chemical history

ALEXANDER ROSS February 8 1964
MACLEAN'S REPORTS

SCIENCE

How Neil Bartlett broke an old law and won his place in chemical history

ALEXANDER ROSS February 8 1964

SCIENCE

How Neil Bartlett broke an old law and won his place in chemical history

SCIENTIFIC RULES are made to be broken, and breaking them often takes much less time and effort than, say, Madame Curie devoted to the discovery of radium. That, at least, was the experience of a thirty-one-year-old University of British Columbia researcher named Neil Bartlett. Bartlett spent less than a week of laboratory time on an experiment that created a compound never before seen on earth, and overturned a scientific dogma that had stood unchallenged for at least fifty years.

Working in his cluttered laboratory in UBC’s chemistry building in March/1962, Bartlett pumped a reddish gas called platinum hexafluoride into one end of a glass assembly shaped like a small upended barbell. Into the other bulb went a colorless gas called xenon, a rare element found in minute quantities (about one part per twelve million) in ordinary air. The two gases were separated by a glass membrane in the middle of the tube connecting the bulbs. Then, using a toy magnet, he lured a small ball-bearing from its shelf in the top bulb. It fell down the connecting tube, broke the glass membrane with an audible tinkle and dropped into the bulb below. Instantly, the two gases combined to form a yellow' powder that coated the inside of the apparatus.

“And that's all there was to it,” recalls Bartlett. “I didn’t shout 'eureka’ or anything. I confirmed the result by repeating the experiment, then w'ent home and told my wife about it. She saw I was excited but I'm not sure she understood what I was talking about.”

But researchers around the world realized the significance of Bartlett's experiment. By combining xenon with another chemical to form a compound called xenon hexafluoroplatinate, he had disproved the notion that xenon is chemically inert. Ever since Sir William

Ramsay and M. W. Travers discovered it in 1898 xenon has been included in the “noble gas” group of elements — gases that show no inclination whatsoever to combine with other substances.

The aloofness of these gases — the others are helium, argon, neon, krypton and radon — has had an important bearing on valence theory which is the branch of chemistry that tries to explain how and why the elements combine with each other. Because these gases did not combine to form true compounds chemists were able to construct theories about the electronic structure of the elements that did.

Bartlett's discovery may lead to reassessments of prevailing valence theory. Meanwhile, it means chemistry textbooks the world over have to be revised. Most of them — including the one Bartlett used as a high-school student in Newcastle — describe xenon as an “inert gas.”

The scientific community has pointed to Bartlett's achievement as an excellent example

of the value of scientific skepticism. Most chemists tended to assume that the noble gases wouldn't form compounds simply because no one had managed to make them combine. By attempting something chemists assumed couldn't be done, Bartlett earned himself a small but secure niche in the history of scientific enquiry.

INGREDIENTS OF DISCOVERY: EFFORT, SKEPTICISM

Science, the prestigious journal of the American Association for the Advancement of Science, hailed the discovery: “For perhaps fifteen years, at least a million scientists all over the world have been blind to a potential opportunity to make an important discovery. All that was required to overthrow an entrenched and acceptable dogma was a few hours of effort and a germ of skepticism.”

Bartlett's skepticism was aroused in 1961 when he began tinkering with platinum hexafluoride, first produced in 1957 at the Argonne National Laboratory in Illinois. Bartlett noticed that it was an extremely potent oxidizing agent. Asbestos and glass will “burn” in an atmosphere of pure fluorine, but Ar-

gonne's chemical was about twice as adept as fluorine in removing electrons from other compounds. If any substance could induce an inert gas to form a compound, he reasoned, it was platinum hexafluoride. And so, using standard laboratory procedures, he went ahead and tried the experiment. “From thinking about it to doing it took about a month,” he says. “But I spent most of the time waiting for xenon to arrive in the mail.”

As a tribute to the achievement Bartlett recently became the first recipient of the E. W. R. Steacie Memorial Fellowship, a new Canadian award named after the late head of the National Research Council. It will enable him to conduct pure research at UBC — no teaching, no administration — for the next two years. He'll spend the time trying to form new fluorine compounds, in an attempt to learn more about the still mysterious forces that make chemicals combine with one another. This research might involve experiments with some of the other noble gases, which Bartlett now suspects might not be so noble after all.

ALEXANDER ROSS