From alkali bismuthides

To a dark red solution of sodium bis(4-chlorophenyl)bismuthide, prepared from bis(4-chloro-phenybiodobismuthine (2.8 g, 5 mmol), sodium (0.23 g, 10 mmol) and liquid ammonia (150 ml), was added 1-iodonaphthalene (1.27 g, 5 mmol) in ether (10 ml). Evaporation of ammonia 

Organobismuth(in) compounds with Bi-group 14 element bonds 

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Bismuthides. Many intermetallic compounds of bismuth with alkali metals and alkaline earth metals have the expected formulas M3Bi and M3Bi2, respectively. These compounds are not salt ike but have high coordination numbers, interatomic distances similar to those found in metals, and metallic electrical conductivities. They dissolve to some extent in molten salts (eg, NaCl—Nal) to form solutions that have been interpreted from cryoscopic data as containing some Bi3 . Both the alkali and alkaline earth metals form another series of alloylike bismuth compounds that become superconducting at low temperatures (Table 1). The MBi compounds are particulady noteworthy as having extremely short bond distances between the alkali metal atoms. 

Phosphides, Arsenides, Antimonides and Bismuthides of Alkali Metals from the Elements... 

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