SYNTHESIS AND CRYSTAL-STRUCTURE OF THE COMPLEX NEPTUNYL CARBONATE [(CN3)(4)N](4)[NPO2(CO3)(3)]CENTER-DOT-8H(2)O

Complex neptunyl carbonate [(CH3)(4)N](4)[NpO2(CO3)(3)]. 8H(2)O was sy nthesized by slow carbonation of a 1 M solution of tetramethylammonium hydroxide containing 0.1 M of NpO2(NO3)(2). X-ray diffraction study ( Siemens PS/PC autodiffractometer) showed that the crystal lattice of t he compound consists of alternating anionic and cationic layers. Cryst allization water molecules participate in formation of anionic layers with the composition {[NpO2(CO3)(3)]. 8H(2)O}(n)(4n-). The structure o f [(CH3)(4)N](4)[NpO2(CO3)(3)]. 8H(2)O is compared with structures of other tricarbonate complexes of actinides(VI).