Although he is primarily known for his work as a chemist, Linus C. Pauling actually was quite prolific and proficient in several different fields, including physics, molecular biology, and other disciplines. He was also well known for being a peace activist, published author, and professor. These disciplines all culminated in his winning multiple Nobel Prizes, including the Chemistry and Peace prizes. That makes him only one of four individuals to ever win more than one prize in their lifetime, which many felt was well deserved for his dedication to peace and ongoing contributions to the world of science at the same time.
In terms of his scientific achievements, Linus C. Pauling was responsible for the practice of applying electronic diffraction, quantum mechanics, and X-ray theories to the field of chemistry. This had never before been combined, and yielded an array of exciting results that were worked on by teams of researchers and then the results published for the public and ongoing interest of the scientific community. That included his theories that were related to rare gas compounds, and a mechanistic theory of enzymes which was developed in 1946. The first Nobel Prize that was awarded to Pauling was the chemistry prize, which he received in 1954 for his work on the properties of different chemical bonds.
In addition to his scientific work in the nuclear field, Linus C. Pauling was also passionately outspoken against nuclear weapons. He worked top ban nuclear weapons testing, for which he was rewarded with the Nobel Peace Prize in 1962. He gave lectures and published a number of writings against nuclear proliferation, hoping to stop the spread of this new deadly type of technology throughout the world. These words were then published in books, and he continued to be outspoken in this area even after the cold war ended.
Other achievements that Linus C. Pauling received included inventing the concept of electro-negativity, which up to that point had never before been heard of, and opened his own Linus Pauling Institute of Science and Medicine in 1973 to help educate a new generation of scientists and allow facilities for further research studies. In 1975 he was awarded the National Medal of Honor by the government, and in his later years worked on the development of quantum mechanical theory, including the Valence and Resonance theory that was an emerging field at the time and is still being worked on to this day.