Alenium is the main power source for aliens technologies and powers all but the largest of ships. One of the primary resources in Xenonauts, It can be recovered from UFO landings and crash sites and is needed for the construction and research of all advanced technology.
In-game description Edit
Alenium is the fundamental power source for all alien technology. It is a translucent yellow material that resembles amber in appearance and forms the core of the alien power source recovered (the rest of the device ultimately proving inconsequential).
Detailed analysis of Alenium's molecular structure reveals an incredibly dense atomic arrangement, allowing the material to store energy in quantities previously thought impossible. Despite this, the material remains inert and has a half-life of nearly a trillion years. It can be cracked if enough mechanical force is applied, but this will not cause an energy discharge. This can be explained by the exceptionally stable arrangement of atomic chains, which also contain a clue as to unlock the energy trapped within: each chain contains regular "weak" bonds that can be broken with precise application of energy. By specifically targeting and breaking these weak bonds with a laser, one can easily generate a controlled energy release of virtually any size.
This leads me to believe that Alenium is no more than a incredibly advanced alien battery. The molecular structure is not one the would occur naturally nor contain any inherent energy of it's own, but it makes a perfect method for storing the output from a far greater power source. As we have no way of recharging Alenium and will almost certainly be using it to power any new technology we develop, we should make an effort to recover as much as possible from UFOs and alien ground forces.
How to research and acquire it: Edit
Alenium is discovered early game and can be researched once you have acquired some of it. Alenium can be found on nearly every alien vessel (other than the light scout).