EFFECT OF HYDROSTATIC-PRESSURE ON THE PHASE-TRANSITIONS IN [N(CH3)4]2ZNI4, [N(CH3)4]2CDI4, [N(CH3)4]2HGCL4, AND [N(CD3)4]2MNCL4

The effect of hydrostatic pressure on the phase transitions in {N(CH3)4}2XY4 (XY4 = Zn14, Cd14, HgC14) and in a deuterated compound of {N(CD3)4)2MnC14 have been studied. The intermediate monoclinic phase in the -Zn14 compound narrows as pressure increases, anddisappears at 176 MPa. The transition temperatures in the -Cd14 and -HgC14 compounds increase linearly with increasing pressure with the rates of 0.22 K/MPa and 0.20 K/MPa, respectively. The pressure-temperature phase diagram of IN(CD3)4]2MnC14 is similar tothat of the hydrogencompound. The appearance of the dielectric-constant peak in the incommensurate phase shifts towards about 35 MPa higher pressure by deuteration. © 1990, Taylor & Francis Group, LLC. All rights reserved.