bismuth
Chemical element with symbol Bi and atomic number 83. Used in alloys, cosmetics, and pharmaceuticals.
See also: ビスマス
Sōen is a metallic element also called bismuth.
This alloy contains bismuth.
The kanji 蒼 (blue) and 鉛 (lead) were chosen to describe the element's bluish-white appearance and metallic nature. The reading そうえん is the on'yomi of these characters.