Physical properties of stable monoclinic and metastable trigonal 4-methylbenzophenone

Pyroelectric, dielectric and piezoelectric coefficients of metastable 4-met hylbenzophenone, point group 3, have been determined by standard methods. F urther more, thermal expansion and elastic properties of this phase and of the stable monoclinic phase have been studied. The pyroelectric effect is c omparable with that of tourmaline, the piezoelectric effects to those of cc -quartz. The differences between the two polymorphs with respect to thermal expansion and to elastic and thermoelastic properties are small, but never theless significant.