Die Kettenstruktur der hydratisierten Tetramethylammoniummangan(II)-hexacyanometallate(III) NMe₄MnFe(CN)₆ · 8 H₂O und NMe₄Mn₂(CN)₆ · 8 H₂O / The Chain Structure of the Hydrated Tetramethylammoniummanganese(II)-hexacyanom etallates(III) NMe₄MnFe(CN)₆ · 8 H₂O und NMe₄Mn₂(CN)₆ · 8 H₂O

Abstract

<jats:p>The crystal structures of the isomorphic tetragonalcompounds NMe<jats:sub>4</jats:sub>MnFe(CN)<jats:sub>6 </jats:sub>·8 H<jats:sub>2</jats:sub>O (a = 1067.0, c = 1056.8 pm ) and NMe<jats:sub>4</jats:sub>Mn<jats:sub>2</jats:sub>(CN)<jats:sub>6 </jats:sub>· 8 H<jats:sub>2</jats:sub>O (a = 1066.9, c = 1064.1 pm ), space group P4/n, Z = 2 , were determined (R = 0 .03). The structure is built up from slightly distorted M(CN)<jats:sub>6</jats:sub><jats:sup>3−</jats:sup> octahedra and square planar Mn(H<jats:sub>2</jats:sub>O)<jats:sub>4</jats:sub><jats:sup>2+</jats:sup> cations, stacked one upon the other in nearly eclipsed positions to form cyanobridged chains - Mn -NC -Mm -CN -along [001]. The average distances in the compounds are: Fe -C = 193.8 (Mn -C -199.3) pm, C -N = 114.7 (114.7 ) pm , Mn -N = 220 .2 (218 .2) pm, Mn -O = 218 .8 (218 .5) pm. The differences of bridge lengths are discussed, as well as the orientation and contact distances of the tetramethylammonium cations. These and additional crystal water, forming H -bonded(H<jats:sub>2</jats:sub>O)<jats:sub>4</jats:sub> rings, occupy positions in the center of elpasolite- like sub cells, which result from O -H ··· N bridging between different chains. Some further relations to the structures of elpasolite and prussian blue are pointed out.</jats:p>