@_@ element has no special purpose at the moment, like Glow used to be before photons. What it does do is it displays physical properties that are inverted from the norm. When heated it turns solid, and when cooled it turns into gas.
The idea is to have an element with these unusual properties to help with mechanics when someone needs it.
Same with ANAR, it actually moves with inverted velocity, meaning that if a bomb goes off, ANAR will be sucked -into- the explosion.