The Nobel Prize in Chemistry has been awarded to two scientists for developing "an ingenious tool for building molecules" that is both inexpensive and environmentally friendly.

The award will be shared by Benjamin List of the Max Planck Institute for Coal Research in Germany and David MacMillan of Princeton University in the United States, according to the Royal Swedish Academy of Sciences.

The pair were announced as the prize winners for the development of asymmetric organocatalysis in Stockholm, Sweden on Wednesday,

Their discoveries "initiated a totally new way of thinking for how to put together chemical molecules," Pernilla Wittung-Stafshede, a member of the chemistry Nobel committee, said.

"This new toolbox is used widely today, for example in drug discovery, and in fine chemicals production and is already benefiting humankind greatly," Wittung-Stafshede added.

Chemists have traditionally utilized enzymes or metal catalysts. Small organic molecules, however, can be used to drive a wide range of chemical processes, as discovered by these two researchers. To describe the new concept, MacMillan invented the term "organocatalysis."

Organocatalysis is particularly effective when researchers wish to synthesize a molecule and choose to produce one of its two mirror counterparts, the Nobel committee said. This has shown to be especially critical in the case of pharmaceuticals.

List and MacMillan's work has aided in the development of a medicine to treat high blood pressure, as well as the creation of drugs such as paroxetine (Seroxat), which is used to treat depression, and oseltamivir (Tamiflu), which is used to treat respiratory infections.

When asked how he felt about winning, Princeton University's MacMillan remarked

"Dazed, confused, elated, proud, sentimental, weepy - you name it," MacMillan said when asked how he felt about winning. "I feel all of those things right now."

"I absolutely didn't expect this huge surprise," List said, adding that he "thought it was a joke" when he received the call from Sweden.

The 10 million krona (£842,611) prize money will be split among the winners.

The Nobel Prizes for Science have been criticized in recent years for being overwhelmingly awarded to men. Before this announcement, 185 people had won the Nobel Prize in Chemistry. Only seven of the participants were female. This year's Nobel Prize winners in medicine, physics, and chemistry were all men.