CdHgO2: Ein Oxomercurat mit Verwandtschaft zur Crednerit-Struktur

CdHgO₂: An Oxomercurate related to the Crednerite Structure Single crystals of CdHgO₂ were prepared by oxygen high pressure technique (600°C, 3900 bar) and investigated by X-ray technique. It crystallizes with monoclinic symmetry, space group C–C2/m; a = 5.933, b = 3.452, c = 5.875 Å, β = 91.26°; Z = 2. The Hg²⁺ ions show dumb-bell like coordination, Cd²⁺ an octahedral one. CdHgO₂ shows strong relationship to the Crednerite structure. The orientation of the O? Hg? O dump-bells to the CdO₆ octahedra layers is discussed with respect to related oxomercurates.     

Littlewood's One Circle Problem

It is shown that Littlewood's one circle problem has a negativeanswer, that is, there exists a continuous bounded functionf on the unit disk U such that f is not harmonic, but neverthelessfor every x U the equality holds for some r(x) with 0 < r(x) < 1 – ||x||.