The bismuthide ion is but the term is often used to describe less reduced forms of bismuth.
Bismuthides are compounds of bismuth with more electropositive elements. A wide variety are known.
The stoichiometry of bismuthides ranges from lithium bismuthide (Li<sub>3</sub>Bi), which can be viewed as the Li<sup>+</sup> salt of Bi<sup>3-</sup>. The corresponding sodium and potassium derivatives are also known. They all prepared by heating the elements.
In terms of Bi-rich phases, examples are LiBi, KBi<sub>2</sub>, CaBi<sub>3</sub>, which exhibit strong Bi-Bi bonding. Some are intermetallic compounds, containing partially metallic and partially ionic bonds. The majority of bismuthides adopt efficient packing arrangements and become densely packed structures, which is a characteristic of intermetallic compounds.