is Orthophenylisopropylisocyanat...
It has the molar weight of 242.5 and is havier then uran (that is 236 and 238 me thinks)
It does not radiate like uran but has the hang to get bigger and bigger....
It normallly appears on forums (big source on UTA forum) otherwise u can find it deep in earth core
It´s used for communication systems and a very unique source there...
Commercial price for = 13.5$ per 100g