We have investigated elastic, magnetic, thermal and structural properties of systems which exhibit induced magnetic behavior (TbP, PrSn3, Pr3Se4, Pr3Te4). Particular emphasis is given to phonon effects due to the crystalline electric field, phase transitions, and magnetic fields. TbP has a first order magnetic phase transition and both TbP, PrSn3 show a temperature dependence of the elastic constants, which can be explained with the known crystal field level scheme. The compounds Pr3S4, La3S4, Pr3Se4 exhibit structural instabilities at much higher temperatures than the magnetic or superconducting transition temperatures. Pr3Te4 does not exhibit a structural transition, but a strong elastic softening in a magnetic field. This effect is due to strong field dependent quadrupole transitions. All these systems are analyzed with respect to typical induced moment parameters.