Pauling was an amazing American scientist. To date he is the only person to be awarded two unshared nobel prizes in different fields.1 In 1954 he won the Nobel prize in Chemistry for his work on the chemical bond. He helped develop the chemistry theories of resonance, ionic bonding, and hybridization.
His understanding of the atom made him an obvious scientist to invite to work on the Manhattan Project, the joint venture between the United States, Canada, and the United Kingdom to develop the atom bomb. He chose not to participate. Instead he chose to work on development of rocket propellants, synthetic quartz, and artificial blood serum. He was an peace activist during and following World War II. This peace activism led to him receiving the Nobel Peace Prize in 1962.2
Unfortunately Pauling's story doesn't end here. No honest biography of Linus Pauling can exclude his ventures into pseudoscience. Although he is responsible for many advances in chemistry, he is also responsible for the widespread belief that large amounts of Vitamin C can prevent the common cold. Pauling proposed that doses of 1,000 mg of vitamin C daily will reduce the incidence of colds by 45% for most people but that some people need much larger amounts.3 When controlled studies of Vitamin C treatments were shown to be ineffective, Pauling doubled down, claiming that 75% of cancers can be prevented and cured by Vitamin C alone. In fact, Vitamin C increases the rate of cancer growth at doses of 1 to 5 grams per day, and only suppresses the cancer growth rate at doses on the order of 100 grams per day (which is close to the lethal dose).
So is Linus Pauling wrong for having a bad idea? No, but when presented with evidence to the contrary he refused to accept the evidence. Pauling won two Nobel prizes, and this is one proof that proponents of Vitamin therapy give to validate the treatment. This is the logical fallacy known as "Argument from Authority". An expert opinion cannot be used to prove the validity of an argument. Pauling's opinion, even as a Nobel prize winning chemist, does not influence the veracity of his arguments on Vitamin C. They must stand on their own (which they haven't). Similarly, Pauling's opinion on his Nobel prize winning work doesn't influence the veracity of his work. It too must stand on its own (which it has).
Notes
[1] Marie Cuire won two nobel prizes (Chemistry and Physics), but her husband shared the prize for Physics with her husband, Pierre.
[2] An interesting fact. Pauling's activism brought with it suspicion of being a communist supporter and he was denied a passport in 1952. Luckily he was able to clear things up by 1954 and was able to accept his 1954 Nobel Prize in Chemistry. In 1962 he was awarded a Nobel prize for the same reason that nearly kept him from accepting his first Nobel prize.
[3] From his book "Vitamin C and the Common Cold" written in 1976.