STUDIES ON ABX(6) COMPOUNDS .5. THERMODYNAMICS AND KINETICS OF THE HIGH-PRESSURE TRANSFORMATIONS ON ABX(6) COMPOUNDS (A=CA, DY, GE, SN, PB,B=TH, U, X=I)

The results of high pressure experiments with ternary iodides of the g eneral formula ABI, with A = Ca, Dy, Ge, Sn, Pb and B = Th, U are desc ribed. These compounds transform from a beta- to a gamma-SnThI6-type s tructure, both variants of known trihalide structures (BiI3- and PuBr3 -type). Trends and pecularities in the values for the minimal transfor mation pressures and in the velocities of transition are pointed out, and they are discussed in terms of geometric and electronic factors.