Researchers at Haifa's Technion-Israel Institute of Technology have discovered six different crystal forms - instead of the one known until now - of TATP (acetone peroxide), an organic explosive that takes the form of a white crystalline powder with a distinctive acrid smell. The discovery, said the Technion, will make it possible to develop better technologies for detecting the explosive, which is used by terrorist organizations around the world. TATP is highly susceptible to heat, friction and shock, but its instability is changed by impurities in the chemical, which is normally stable when pure. It is one of the few explosives which is explosive when wet or kept underwater. Apparently used in the lethal July 2005 bombings in London, TATP is dubbed by some Islamic terrorist organizations as "Mother of Satan" because of its instability. Acetone peroxide was discovered in 1895 by Richard Wolffenstein, the first researcher to get a patent for using the peroxide as an explosive compound. Prof. Ehud Keinan of the Technion's chemistry faculty headed the research and said that the explosive can appear in six crystal forms depending on the conditions of its synthesis and its crystallization. He added that to his surprise, TATP proved to be very unusual, with different characteristics compared to those of conventional explosives used for legal civilian or military. "In the past, we discovered that TATP explosions do not release heat, so it is similar to that material contained in vehicle air bags to help protect passengers during crashes," said Keinan. He and his team discovered the structure of all six crystals using x-rays and additional techniques. Their findings have just appeared in the journal Crystal Growth & Design. Keinan, who is president of the Israel Chemical Society, explained that TATP is popular among terrorist organizations because it is made quite easily from cheap materials and difficult to detect. The new discovery will make it easier to identify using x-ray and other techniques, he said. TATP was used by Arab terrorists to murder victims at the Tel Aviv Dolphinarium, Jerusalem's Ben-Yehuda mall and in bus bombings. Previously, Technion researchers developed a unique mechanism to detect TATP and other peroxide explosives using Acro-PET, a pen-like device with three colors. It releases three chemical compounds that causes color changes after being in contact with explosive samples.