Ice-nine is a fictional material appearing in Kurt Vonnegut's novel Cat's Cradle. Ice-nine is supposedly a polymorph of water more stable than common ice (Ice Ih); instead of melting at 0 °C (32 °F), it melts at 45.8 °C (114.4 °F). When ice-nine comes into contact with liquid water below 45.8 °C (thus effectively becoming supercooled), it acts as a seed crystal and causes the solidification of the entire body of water, which quickly crystallizes as more ice-nine. As people are mostly water, ice-nine kills nearly instantly when ingested or brought into contact with soft tissues exposed to the bloodstream, such as the eyes.
In the story, it is developed by the Manhattan Project in order for the Marines to no longer need to deal with mud, but abandoned when it becomes clear that any quantity of it would have the power to destroy all life on earth. A global catastrophe involving freezing the world's oceans with ice-nine is used as a plot device in Vonnegut's novel.
Vonnegut came across the idea while working at General Electric:
- The author Vonnegut credits the invention of ice-nine to Irving Langmuir, who pioneered the study of thin films and interfaces. While working in the public relations office at General Electric, Vonnegut came across a story of how Langmuir, who won the 1932 Nobel Prize for his work at General Electric, was charged with the responsibility of entertaining the author H.G. Wells, who was visiting the company in the early 1930s. Langmuir is said to have come up with an idea about a form of solid water that was stable at room temperature in the hopes that Wells might be inspired to write a story about it. Apparently, Wells was not inspired and neither he nor Langmuir ever published anything about it. After Langmuir and Wells had died, Vonnegut decided to use the idea in his book Cat's Cradle.
The fictional ice-nine should not be confused with the real-world ice polymorph Ice IX, which does not have these properties.
- While multiple polymorphs of ice do exist (they can be created under pressure), none have the properties described in this book, and none are stable at standard temperature and pressure above the ordinary melting point of ice. The real Ice IX has none of the properties of Vonnegut's creation, and can exist only at extremely low temperatures and high pressures.
- The ice-nine phenomenon has, in fact, occurred with a few other kinds of crystals, called "disappearing polymorphs". In these cases, a new variant of a crystal has been introduced into an environment, replacing many of the older form crystals with its own form. One example is the anti-AIDS medicine ritonavir, where the newer polymorph destroyed the effectiveness of the drug until improved manufacturing and distribution was developed.
- The Boston-based metalcore band Ice Nine Kills is named after Vonnegut's weapon of mass destruction.
- Chris Mars' 1993 album 75% Less Fat includes a song called "No More Mud" which is entirely about Ice-Nine and makes numerous references to the characters of the book.
- Joe Satriani's instrumental album Surfing With the Alien includes a track "Ice 9".
- The One O'Clock Lab Band at UNT performed an original jazz composition called "Ice-Nine" (composed by Steve Wiest) on their Grammy nominated album Lab 2009 which is sold exclusively through Penders Music Company
- Musician Susumu Hirasawa named a guitar of his design "ICE-9"; he also released an album to showcase the guitar, also named ICE-9.
- The video games 999: Nine Hours, Nine Persons, Nine Doors and its sequel Virtue's Last Reward use "ice-9" as a minor plot element, with attributes similar to Vonnegut's original ice-nine.
- The 2003 film The Recruit features a computer virus named Ice-9 in tribute to Vonnegut's ice-nine that would erase hard drives and travel through power sources which are not protected, possibly erasing the hard drive of every computer on Earth.
- The Season 4 Episode "Ice" of the American television show Alias revolves around a chemical named Ice-Five with the same effect as Vonnegut's Ice-Nine.
- Red Mage Statscowsky, a main character in the popular web comic series 8-Bit Theater can and has used a spell known as "Ice-9" which will stop all thermal activity of the dimension it's used in.
- Ice-9 appears in The League of Extraordinary Gentlemen, Volume III: Century. It forms the tomb of Golden Age superhero Stardust.
- Some part of the Scheme programming language implementation GNU Guile is named ice-9 with regard to the crystallization effect of Vonnegut's invention.
- The rock band the Grateful Dead set up a publishing company called Ice Nine (in tribute to Vonnegut's story).
- In Biology prions are linked conceptually to Ice-nine (which is often used as a fictional example of prions in the classroom). This is because prions and Ice-nine are both self-propagating alternate forms of a material (water in the case of ice-nine and a protein in the case of prions)
- Liberko, Charles A. (2004). "Using Science Fiction To Teach Thermodynamics: Vonnegut, Ice-nine, and Global Warming". Journal of Chemical Education 81 (4): 509. doi:10.1021/ed081p509.
- Morissette SL, Soukasene S, Levinson D, Cima MJ, Almarsson O (March 2003). "Elucidation of crystal form diversity of the HIV protease inhibitor ritonavir by high-throughput crystallization". Proc. Natl. Acad. Sci. U.S.A. 100 (5): 2180–4. doi:10.1073/pnas.0437744100. PMC 151315. PMID 12604798.
- Lansbury PT, Caughey B (January 1995). "The chemistry of scrapie infection: implications of the 'ice 9' metaphor". Chem. Biol. 2 (1): 1–5. doi:10.1016/1074-5521(95)90074-8. PMID 9383397.