ON THE EXISTENCE OF POLYNARY OXIDES OF THE ALKALI-METALS WITH MONOVALENT COBALT AND NICKEL

For the first time we obtained RbNa2NiO2, KNa2NiO2, Na3CoO2 and K3CoO2 [RbNa2NiO2: Na2NiO2 + Rb2O, Rb:Ni = 1.8:1, 600-degrees-C, 28 d, Ni-tube; KNa2NiO2: Na2NiO2 + K2O, K:Ni = 1.8:1, 600-degrees-C, 20 d, Ni-tube; Na3CoO2: Na2O + CoO: Na:Co = 8.8:1, 500-degrees-C, 20 d, Co-tube; K3CoO2: K2O + CoO: K:Co = 4.4:1, 550-degrees-C, 20 d, Co-tube]. According to X-ray structure analysis of single crystals monovalent Co and Ni is present [always four-circle-diffractometer data, MoKalphaBAR-radiation; RbNa2NiO2:AED 2, all 163 I(o)(hkl), R = 3,4%, R(w) = 1.9%, I4/mmm, a = 461.7(1), c = 973.6(3) pm, Z = 2; KNa2NiO2: AED 2, all 341 I(o)(hkl), R = 5.6%, R(w) = 3.5%, Cmma, a = 1048.5(3), b = 626.8(1), c = 621.9(1) pm, Z = 4; Na3CoO2: PW 1100, 517 of 568 I(o)(hkl), R = 2.9%, R(w) = 1.80%, P4(2)/mnm, a = 940.0, c = 464.5 pm, Z = 4; K3CoO2: PW 1100, all 940 I(o)(hkl), R = 5.0%, R(w) = 3.9%, Pnma, a = 1190.0, b = 730.4, c = 604.1 pm, Z = 4]. All samples are red, the single crystals transparent. Two O2- coordinate Ni1+ and Co1+, respectively, like a dumb-bell. Mean Fictive Ionic Radii, MEFIR, and Effective Coordination Numbers, ECoN, and Madelung part of lattice energy, MAPLE, are given.