Left metal radical, the side-form of 金 - the indexing element. Marks 铂 as a chemical element: platinum, the silvery-white precious metal prized for catalysts, jewellery and lab crucibles. Same family as 金 gold, 银 silver, 铜 copper.
Right 白 supplies the sound, drifting bái to bó with tone change. Strong semantic flavour: 白 means 'white', and platinum is famously bright white - sometimes called 白金 'white gold' in everyday Chinese. Family: 拍, 泊, 伯, 柏.
