In a piezoelectromagnetic crystalline medium belonging to the class 2 of the
monoclinic crystallographic system we find some classes of piezoelectricity-induced
electromagnetic waves. These are time harmonic plane waves propagating along the
symmetry axis and depending only on the axial coordinate. There are two indepen-
dent modes of propagation, one longitudinal and one transverse, with mechanical
and electromagnetical couplings. The transverse mode admits as a particular case an
electromagnetic wave with no associated elastic deformation
