Yttrium (element)
釔 refers specifically to the chemical element yttrium. It has no broader conceptual center beyond this single technical meaning.
釔 is a modern character created for the chemical element yttrium, combining the metal radical 金 with the phonetic component 乙 (イツ).
The metal radical 金 tells you it is a metallic element. The right side 乙 looks like a hook, but here it just helps with the sound.
For イツ, imagine a piece of yttrium metal that is so rare it costs one 一 (イチ) and two 二 (ニ) combined, but the reading is イツ, so think of it as a single special unit: イツ.