Barium (element)
鋇 is a rare kanji that refers specifically to the chemical element barium. It has no broader conceptual center beyond this technical meaning.
鋇 is a modern character created to represent the element barium. It combines the metal radical 金 with 貝, which likely serves as a phonetic component (ハイ) rather than a semantic one.
The metal radical 金 hints at a metallic element, and the right side 貝 (shell) can remind you of a rare, valuable substance like barium.
For ハイ, imagine a high-purity barium sample: high -> ハイ, and the metal 金 is highly reactive.