The molecular formula BiH5 suggests a compound containing one bismuth (Bi) atom and five hydrogen (H) atoms. The structure and geometry of the molecule can be derived from the VSEPR theory.
For BiH5, it is expected to have a trigonal bipyramidal geometry (AX5) if we consider that bismuth can expand its valence shell and form five bonds, leading to a configuration with five bonding pairs and no lone pairs.
However, it's worth noting that the known chemistry of bismuth and its light hydrides does not typically include stable BiH5. Instead, compounds like BiH3 (bismuth hydride) are well-characterized, and BiH5 may be theoretical or unstable.
To summarize, if BiH5 were to exist and conform to the AX5 configuration, it would adopt a trigonal bipyramidal shape. However, the stability of such a compound would require further investigation, as no widely accepted references for BiH5 exist in current chemical literature.