Untriseptium

Untriseptium (), also called eka-dubnium or element 137, is a possible chemical element which has not been synthesized. Due to instabilities, it is not known if this element is possible, as the instabilities may hint that the periodic table ends soon after the island of stability at unbihexium. Its atomic number is 137 and symbol is Uts.
The name "untriseptium" is a temporary name.
Importance.
It is sometimes called feynmanium (symbol Fy) because Richard Feynman noted that a simplistic interpretation of the relativistic Dirac equation runs into problems with electron orbitals at "Z" &gt; 1/α = 137, suggesting that neutral atoms cannot exist beyond untriseptium, and that a periodic table of elements based on electron orbitals breaks down at this point. However, a more thorough analysis calculates the limit to be around element 173.