By Paul Rincon
BBC News science reporter
Three scientists have been awarded the 2005 Nobel Prize for Chemistry for improving a process used in making plastics and pharmaceuticals.
The announcement came at the Royal Academy of Sciences in Stockholm
Frenchman Yves Chauvin and Americans Richard Schrock and Robert Grubbs were recognised for their contributions to a reaction process called metathesis.
Their work has made the process of synthesising carbon compounds simpler, more efficient and greener.
Swedish scientist Alfred Nobel founded the prizes in his will written in 1895.
The process of metathesis, or olefin methathesis, allows double bonds to be broken and made between carbon atoms in ways that make atomic groups swap places. The process has been likened to couples changing partners during a dance.
The chemical process takes place with the assistance of special catalyst molecules.
Metathesis is used on a daily basis in the chemical industry, mainly in the production of pharmaceuticals and advanced plastics.
"I am rather embarrassed, because I do not have the true profile," 74-year-old Yves Chauvin, of the French Institute for Petroleum, told Swedish radio after the laureates were announced.
Professor Laurence Harwood, an expert in organic chemistry at the University of Reading, UK, told the BBC News website he was "not one bit surprised" by the subjects of this year's prize.
"It is thoroughly deserved," he added. "The olefin metathesis has had a major and fundamental impact on how organic chemists build their molecules.
"Very rarely do people develop new reactions and this one has widespread applications."
Chauvin provided the crucial explanation
The reaction itself was discovered in the 1950s, emerging out of industry. However, though scientists knew it worked, they could not explain how it worked.
They needed to understand the molecular mechanism by which the catalyst sped the reaction along.
Enter Yves Chauvin, who, in 1970, proposed that the catalyst was a metal carbene, or alkylide. He also presented a new mechanism for the way this metal compound functions in the reaction that explained all previous experimental results using metathesis.
Room for improvement
Later on, other researchers were to develop more efficient catalysts for use in metathesis. In 1990, Richard Schrock, of the Massachusetts Institute of Technology (MIT), US, developed a highly efficient catalyst based on the metal molybdenum.
Another breakthrough came two years later, when Robert Grubbs, of the California Institute of Technology (Caltech), developed a catalyst based on another metal, ruthenium, which was stable in air.
This has found many applications in science and industry.
Richard Schrock developed an effective catalyst for metathesis
In its citation for the 2005 award for chemistry, the Nobel jury declared "fantastic opportunities" had resulted from the trio's work.
Benefits to arise from the findings include advanced herbicides, additives for polymers and fuels, and research into new treatments for bacterial infection, cancer, Alzheimer's disease, arthritis, migraine and HIV.
Their work has also been a step forward for "green chemistry", reducing potentially hazardous waste through smarter production.
"Imagination will soon be the only limit to the kind of molecules that could be built in the future," the Nobel jury said.