Partial molar volumes and partial molar adiabatic compressibilities of potassium trioxalato complexes of Al(III), Fe(III), Co(III), and Cr(III) between 15 degrees and 35 degrees C

The apparent and limiting apparent molal volumes of dilute aqueous solutions of K-3[Al(ox)(3)] . 3H(2)O, K-3[Fe(ox)(3)] . 3H(2)O, K-3[Co(ox)(3)] . 3H(2)O, and K-3[Cr(ox)(3)] . 3H(2)O complexes were determined from density data measured at 15 degrees, 25 degrees, and 35 degrees C. The apparent and limiting apparent molal adiabatic compressibilities of these complexes were determined from measured ultrasonic sound velocities at 15 degrees, 25 degrees, and 35 degrees in dilute aqueous solutions. The volume change associated with complex formation is discussed in terms of the nature of the coordinate bond and the overall hydration behavior of these complexes.