Zur Kenntnis ternärer Oxide des Bleis: Über Na2PbO2

On Ternary Oxides of Lead. The Na₆PbO₅ Na₆PbO₅ (pale yellow) crystallizes orthorhombic in Cmcm with a=10.6₈, b=5.70₉, c=10.9₉, å; Z=1. Parameters were refined by least-squares (479 hkO–hk7, MO–K_α) R=0.112₄, R′=0.116, (parameters see text). Isolated PbO₅ groups of pseudotetragonal pyramids lend Pb⁴⁺ Coordination Number (CN) 5. Along 100] and 010] the pyramids are equivalent orientated, but along 001] alternately twisted by 180°. Na+ occupies holes between O^2?, leading to CN 6 (Na″+) and Na″′⁺ and CN 4 (Na′⁺). The MADELUNG part of lattice energy (MAPLE) is calculated and discussed.