The Swedish Academy chose Henri Moissan over Dmitri Mendeleev by one vote in 1906.
The decision followed an unusually contentious Nobel episode. Mendeleev had been nominated for his periodic system, and the Nobel Committee for Chemistry recommended him for the 1906 Chemistry Prize. The chemistry section of the Swedish Academy supported that recommendation, so the final vote was expected to confirm it.
Instead, the full Academy debated Moissan’s candidacy. Peter Klason proposed Moissan, while Svante Arrhenius used his influence to oppose Mendeleev. The vote was close enough that Moissan prevailed by a single ballot. That narrow margin is why the episode is often cited as one of the great Nobel near-misses: Mendeleev never received the prize, despite being nominated in three successive years.
Moissan’s award recognized his work in isolating fluorine and his related advances in high-temperature chemistry, including the electric arc furnace. The result is sometimes described loosely as a rejection of Mendeleev by the Nobel Committee, but the decisive choice was made by the Swedish Academy after a disputed final meeting. Mendeleev died in 1907, the year after coming within one vote of victory.