Irillium

Irillium (symbol Im, and also known as Livermorium or Lv) is a chemical element, atomic number 116 on the periodic table.

Characteristics and history
Irillium, in its most stable form, has an atomic mass of 305. Unsynthesized deposits of this substance was discovered by Humans for the first time in asteroids, in the Sol star system's asteroid belt, around the year 2029. This metal is part of the trans-uranic series of heavy elements. 

Irillium can exist as a contaminant in ryetalyn deposits. 

Background
In real-life science, element 117 has only recently been discovered, and named "livermorium" (Lv). Some models of theoretical science have stated that heavy elements on this scale cannot exist in nature. Subspace science mentioned in Star Trek may account for the contradiction of this being a resource on other worlds.