KzGe(IO3)6 crystallizes in space group R~ with a = 7"472 A, ~ = 96"68 °, Z= 1. The crystal structure has been determined from three-dimensional single-crystal X-ray data collected on a four circle diffractometer. Using 531 crystallographically independent observed reflexions, the structure was refined to R = 4"0 %. The germanium atoms are surrounded by six oxygen atoms at the corners of a regular octahedron. Each iodine atom has three oxygen neighbours at 1.796, 1.80t and 1.861 ,~ and three others at 2.50-2.98 A, which form a much distorted octahedron. An interesting feature of the structure is that there are two potassium atoms in a tube of 18 oxygens. Each of the potassium atoms is coordinated to nine oxygen atoms at 2.79-2.98 A and to three others at 3.61 A.

Inhaltsübersicht. Blei(IV)‐acetat reagiert in wäßriger Essigsäure mit seleniger Säure zu Blei(IV)‐selenit, Pb(SeO3)2, welches unter geeigneten Versuchsbedingungen mit Alkaliselenitlösungen in die Alkalitriselenitoplumbate(IV), M2[Pb(SeO3)3] übergeführt werden kann (M = NH4, K, Rb, Cs). Die dargestellten Verbindungen sind kristallin. Preparation and Properties of Lead(IV) Selenite, Pb(SeO3)2, and the Alkali Triselenito‐plumbates(IV), M2[Pb(SeO3)3] Lead(IV) acetate reacts in aqueous acetic acid with selenious acid to yield lead(IV) selenite, Pb(SeO3)2. Using suitable conditions of preparation lead(IV) selenite reacts with alkali‐selenites to yield alkali triselenito‐plumbates(lV). M2[Pb(SeO3)3]. All the prepared compounds are cristalline.

Halocuprates(I),

4Die Umsetzung von Zinn(1V)-chlorid mit Hexaoxojod(VI1)-saure fuhrt in Gegenwart von Alkali-Ionen zur Bildung der Verbindungen MSnJ06 (M = NH4, K , Rb, Cs). Die Alkalizinn(1V)-hexaoxojodate(VI1) kristallisieren im hexagonalen System und sind sowohl untereinander als auch mit den Alkali-blei(IV)-hexaoxojodaten(VII)1) isomorph mischbar. Die Gitterkonstanten der hexagonalen Elementarzelle betragen fur NH4SnJ06 a0 = 5.27, co = 12.43, KSnJ06 a0 = 5.27, co = 11.76, RbSnJO6 a0 = 5.27, co = 12.49 und fur CSSnJO6 a0 = 5.27,Co = 13.35 A.

Zn[Pb(IO3)6].6H20 crystallizes in the space group P] with a= 6"905 (7), b= 7"285 (6), c= 10.976 (9) /~, ~=97.2 (1) °, p= 104.15 (8) °, y=88.11 (8) °, Z=I. The intensities were collected on a four-circle diffractometer and corrected for absorption. The crystal structure was determined by the heavy-atom method. Refinement by the least-squares method with anisotropic temperature factors for the heavy atoms (Pb, I,Zn) and isotropic temperature factors for the O atoms converged at R= 4.9 %. The Pb atoms are surrounded by six O atoms belonging to the six -O-102 groups. The O atoms form a distorted octahedron; in particular the distance Pb-O(4) is very short (2-070 A). The I atoms are also surrounded by six O atoms but the octahedron is very distorted. For each I atom there are three I-O distances between 1.766 and 1"898 ,& and three more between 2.546 and 3"083 ~. An interesting feature of the structure is the coordination of the Zn atoms. There is no [Zn(H20)6] 2+ octahedron but instead an octahedron formed by four water molecules and two O atoms of the iodate groups. The other water molecules are embedded in the structure as real structure water. All parts of the structure are linked together by hydrogen bonds.