Acoustic properties of ZrS3−xSex compounds

In the anisotropic ZrSe_3?xSe_x compounds, the velocity of acoustic waves propagating in a direction parallel to the fibers decreases linearly as the Selenium content is progressively increased for 0 < x < 2; in this region of composition two acoustic waves with different velocities are observed. For x > 2, following an increase of velocity, only one acoustic wave is likely to be propagated with a nearly constant velocity. This behavior is tentatively explained by a possible structural transformation taking place at x ～ 2.