SYNTHESIS AND X-RAY STRUCTURE OF NEW COPPER(II) NITRATES - CU(NO3)(2)H2O AND BETA-MODIFICATION OF CU(NO3)(2)

Blue crystals of a Cu(NO3)(2) . H2O were synthesized by interaction of CuO with boiling 100% HNO3. Stable beta-Cu(NO3)(2) modification was o btained by the sublimation of copper(II) nitrate in evacuated ampoule over the 150-->100 degrees C temperature gradient for 24 hr. According to X-Ray single crystal analysis Cu(NO3)(2) . H2O is monoclinic with a = 6.377(1), b = 8.548(1), c = 9.769(1) Angstrom, beta = 100.41(1)deg rees, Z = 4, and space group P2(1)/c. beta-modification Cu(NO3)(2) is orthorhombic with a = 14.161(5), b = 7.516(3), c = 12.886(2)Angstrom, Z = 12, and space group Pbcn. In the both structures Cu atoms are squa re coordinated by 4 O atoms at the distances ranging from 1.92 to 2.02 Angstrom. In each structure there are also additional Cu-O bonds with the distance of 2.33 or 2.35 Angstrom and some weaker ones with the d istances in the range of 2.65-2.72 Angstrom. In the Cu(NO3)(2) . H2O s tructure the [CuO4] squares are connected by the bridging NO3 groups i nto zigzag chains, which are linked into layers by the longer Cu-O bon ds. In the beta-Cu(NO3)(2) structure the [CuO4] fragments of two types are joined by the bridging NO3 groups in a three-dimensional framewor k. Some correlations were found between N-O distances and coordination functions of O atoms.