SYNTHESES, CRYSTAL-STRUCTURES, AND PROPER TIES OF TRISILVER AND TRIPOTASSIUM TRI-MU-IMIDO CYCLOTRIPHOSPHATE, AG-3(PO2NH)(3) AND K-3(PO2NH)(3)

Coarse crystalline Ag-3(PO2NH)(3) (1) and K-3(PO2NH)(3) (2) are obtain ed by addition of an aqueous solution of AgNO3 to an acidified solutio n of Na-3(PO2NH)(3) . 4H(2)O and by diffusion controlled addition of e thanol to a solution of K-3(PO2NH)(3) in water, respectively. The crys tal structures of 1 and 2 have been determined by single crystal X-ray methods (Ag-3(PO2NH)(3): P2(1)/c; a = 1166.6(1), b = 786.4(1), c = 99 7.8(1) pm, beta = 106.91(1)degrees;2 = 4.K-3(PO2NH)(3): R (3) over bar ; a = 1271.4(2), c = 1017.9(2) pm, Z = 6). In Ag-3(PO2NH)(3) the cycli c anion is markedly distorted because of interactions between Ag+ and one nitrogen atom of the anion. In K-3(PO2NH)(3) the trimetaphosphimat e ring shows a chair conformation and two cyclic anions are connected to each other by hydrogen bonds. DTA/TG investigations show thermal de composition above 275 and 250 degrees C for 1 and 2, respectively.