DABHAN HWAHAK HWOEJEEE (Journal of the Korean Chemical Society) Vol. 31, No. 5, 1987 Printed in the Republic of Korea trans- (Cr (tn) 2C12] + trans- [Cr (en) (tn) Cl2] +    t • •   (1987. 2. 11 ) Pressure Effect on the Aquation of trans- [Cr(tn)2Cl2)+ and trans- (Cr (en) (tn) Cl2]+ Complex Ions Jong-Jae Chung \ Jon Ha Choi, and Deog-Jin Kim Department of Chemistry, College of Natural Sciences, Kyungpook National University, Daegu 635, Korea (Received February 11, 1987)  .£n2n" Cr(m)2C12 tn s- Cr(en) (m)CL           .     ,      L7 2. 1 1121-1 .         .                .                       . ABSTRACT. Rates for the aquation of trans~[Cr (tn) 2C12J+ and trans- [Cr (en) (tn)CI2)+ ions in aqueous acidic solution have been measured by spectrophotometric method at various temperatures and pressures. Activation volumes are negative and lie in the limited range — 1.7~ —2.9cm3mol-1 or the complex ions. Activation entropies and activation compressibility coe cients are small negative values. From the results of thermodynamic parameters, it can be inferred that the aquation of the complex ions proceed through an associative interchange (la) mechanism. Furthermore, the information on possible transition state structure and reaction paths can be obtained by considering total stabilization energy of the hypothetical intermediates within the framework of angular overlap model. It is found that the theoretically predicted mechanism is consistent with the experimentally observed results.           *3     . 7 1973 Guastalla 8 Cr(NH3)5X             1979 Eldik 9 Cr(NH3)5H2   H20              . 1984 \ 1 1° ( )(111)  —375—