SYNTHESIS AND STRUCTURE DETERMINATION OF 2 SALTS OF THE TRIMETAPHOSPHIMIC ACID, K-3(PO2NH)(3) AND RB-3(PO2NH)(3)

The reaction between P3N5 and the corresponding alkalimetal hydroxide monohydrate under ammonothermal conditions (6 kbar, 450 degrees C afte r 10 d) in autoclaves leads to the salts of the trimetaphosphimic acid K-3(PO2NH)(3) resp. Rb-3(PO2NH)(3). The structure of K-3(PO2NH)3 was solved by single crystals X-ray methods. The isotypic structure of Rb- 3(PO2NH)(3) was solved by X-ray powder diffraction methods. K-3(PO2NH) (3): R (3) over bar (No. 148), a = 12.615(3) Angstrom, c = 10.224(2) A ngstrom, Z = 6, R-1/wR(2) = 0.0276/0.0726, N(F-o(2) > 2 sigma(F-o(2))) = 769, N(Var.) = 51. Rb-3(PO2NH)(3): R (3) over bar (No. 148), a = 12 .9971(5) Angstrom, c = 10.5485(5), Z = 6, R-Bragg(F-0(2)) = 0.0626, 28 9 reflections. K-3(PO2NH)(3) and Rb-3(PO2NH)(3) contain six-membered r ings P3N3 substituted by oxygen which are connected to double molecule s by N-H ... O bridge bonds. These twin-molecules are stacked in colum ns which form the motive of close packed rods. K+ resp. Rb+ are betwee n these columns. They are coordinated by 6O which belong to 5 differen t rings.