Pergium

Pergium
ELEMENT

Symbol (Terran)	Pe
Atomic number	111
Atomic weight	292

Pergium (symbol Pe) is a chemical element with an atomic number of 111 on the periodic table. Pergium has an atomic mass of 292, and was discovered by Humans for the first time on the planet Mercury in the year 2025. (ST reference: Star Fleet Medical Reference Manual)

Even though pergium was referenced in the SFMRF as being element 111, that element ended up being named roentgenium in real-life, years afterwards. It is possible pergium refers to an as-yet undiscovered isotope or modification to standard roentgenium.

Pergium is typically used in energy production and life support systems by thousands of planets, making it a valuable commodity. One of the Federation's largest sources of pergium in the 23rd century was the mining colony on planet Janus VI, where it was eventually extracted through the joint efforts of the native Horta and Human colonists. (TOS episode: "The Devil in the Dark")

In 2370, Horta miners discovered pergium on The Prodigal, one of Bajor's moons (DS9 novel: Devil in the Sky)

Pergium is a good signal when mining for latinum crystals as they typically form near deposits of the substance. (DS9 novel: Devil in the Sky)

Yanas Tigan and her family owned an operated a pergium facility on Sappora VII. It was once the fifth largest in the sector, until the Ferengi discovered a larger quantity on Timor II and established their own mining concern. (DS9 episode: "Prodigal Daughter")