Yb, or Ytterbium, is a chemical element with the symbol Yb and atomic number 70. It belongs to the lanthanide series of the periodic table and is a silvery-white metal. Ytterbium is known for its applications in various fields, including electronics, lasers, and as a doping agent in certain materials. Ytterbium is relatively stable in air and can be found in minerals such as gadolinite and monazite. It has unique properties that make it useful in creating high-performance optical fibers and in the production of certain types of lasers, contributing to advancements in technology and medicine.