In presenting the Nobel to Dr. Olah in 1994, Salo Gronowitz, of the Royal Swedish Academy of Sciences, said, “Olah’s discovery resulted in a complete revolution for scientific studies of carbocations, and his contributions occupy a prominent place in all modern textbooks of organic chemistry.”

Along the way, Dr. Olah overturned scientific dogma that held that, in organic compounds, a carbon atom could bind to no more than four other atoms. He showed that in carbocations, a carbon atom could bond with five, six or seven neighbors, Dr. Prakash said.

“These are weak bonds, but they’re still held together,” he said. “All of his ideas prevailed.”

George Andrew Olah was born on May 22, 1927, in Budapest, the son of Julius Olah, a lawyer, and the former Magda Krasznai. He attended what he described as one of the best schools in Budapest run by the Piarist Fathers, a Roman Catholic order.

He never described himself as Jewish, but in his autobiography, “A Life of Magic Chemistry,” he referred to that heritage in recalling World War II. “I do not want to relive here in any detail some of my very difficult, even horrifying, experiences of this period, hiding out the last months of the war in Budapest,” he wrote. “Suffice it to say that my parents and I survived.”

After the war, he attended the Technical University of Budapest, obtaining master’s and doctoral degrees. He was an assistant professor of organic chemistry at the university and then appointed deputy director at the Central Research Institute of Chemistry of the Hungarian Academy of Sciences.

In 1949 he married Judith Lengyel, a technical secretary at the university, whom he had known from his early youth. She went on to study chemistry, as well.

In fleeing Hungary after the 1956 uprising, Dr. Olah and his family made brief stops in Vienna and London, where his wife had relatives, before moving to Montreal, where his mother-in-law lived.