It's the chemical symbol for bismuth
[DOC] [TLE] BISMUTH | Bi - PubChem [PAR] BISMUTH | Bi | CID 5359367 - structure, chemical names, physical and ... 
BISMUTH is a metallic element that has the atomic symbol Bi, atomic number 83 
...... air does not affect metallic bismuth and the element preserves its metallic 
luster;... [DOC] [TLE] bismuth (Bi) | chemical element | Britannica.com [PAR] Bi the most metallic and the least abundant of the elements in the nitrogen group 
... Its naturally occurring compounds are chiefly the oxide (bismite or bismuth .... 
Bismuth atoms have the same electronic structure in their outermost shell as do... [DOC] [TLE] It's Elemental - The Element Bismuth [PAR] The Element Bismuth.