Hydrated hexacyanometallate(III) salts of triaqua(18-crown-6)lanthanoid(III) and tetraaqua(18-crown-6) lanthanoid(III) cations containing nine- and ten-coordinate lanthanoids

Tetraaqua( 18- crown- 6) cerium( III) hexacyanoferrate( III) dihydrate, [ Ce( C12H24O6)( H2O)(4)][ Fe( CN)(6)]center dot 2H(2)O, and tetraaqua( 18- crown- 6) neodymium( III) hexacyanoferrate( III) dihydrate, [ Nd( C12H24O6)( H2O)(4)][ Fe( CN)(6)] center dot 2H(2)O, are isomorphous and isostructural in the C2/ c space group, where the cations, which contain ten- coordinate lanthanoid centres, lie across twofold rotation axes and the anions lie across inversion centres. In these compounds, an extensive series of O - H center dot center dot center dot O and O - H center dot center dot center dot N hydrogen bonds links the components into a continuous three- dimensional framework. Triaqua( 18- crown- 6) lanthanoid( III) hexacyanoferrate( III) dihydrate, [ Ln( C12H24O6)( H2O)(3)][ Fe( CN)(6)]center dot 2H(2)O, where Ln = Sm, Eu, Gd or Tb, are all isomorphous and isostructural in the P (1) over bar space group, as are triaqua( 18- crown- 6) gadolinium( III) hexacyanochromate( III) dihydrate, [ Gd( C12H24O6)( H2O)(3)][ Cr( CN)(6)] center dot 2H(2)O, and triaqua( 18- crown- 6) gadolinium( III) hexacyanocobaltate( III) dihydrate, [ Gd( C12H24O6)( H2O)(3)][ Co( CN)(6)] center dot 2H(2)O. In these compounds, there are two independent anions, both lying across inversion centres, and the lanthanoid centres exhibit nine- coordination; in the crystal structures, an extensive series of hydrogen bonds links the components into a three- dimensional framework.