Radiopolarographic determination of the stability constant of 18-crown-6 complex for Ra2+

Thermodynamics of complexation of aqueous 18-crown-6 with barium ion: apparent molar volumes and apparent molar heat capacities of aqueous (18-crown-6+barium nitrate) at temperatures (278.15 to 393.15) K, at molalities (0.02 to 0.33) mol·kg−1, and at the pressure 0.35 MPa

“…These values are the average of 12 and 10 literature values for these two quantities, respectively, for reaction (3). The literature values were obtained by calorimetry [2,4,[6][7][8]10], polarography [11], and conductometry [5,9] with Cl À [2,4,5,[7][8][9][10][11] or NO À 3 [6] as the anion. The scatter in these literature values appears to be unrelated to method or anion investigation.…”

“…The literature values of D r H m and lg K for the formation of (18C6-Ba 2+ ) in water at T = 298. 15 generally showed good agreement [2][3][4][5][6][7][8][9][10][11][12], with the reported values of lg K showing some scatter. A few investigators also reported values at other temperatures [2][3][4].…”