A commonly used pentavalent material is:

Solution (By Examveda Team)

The conductivity of semiconductor material can be improved by doping, i.e., by adding an impurity element with either three or five valence electrons, called, respectively, trivalent (e.g., boron (B) and aluminum (Al)) and pentavalent (e.g., phosphorus (P) and Arsenic (As)) elements. A semiconductor is called either intrinsic or extrinsic, depending on whether it contains any doped impurity.