Hydrothermal syntheses, crystal structures and thermal stabilities of three lanthanide(III) diphosphonates

Three lanthanide diphosphonates, [NH3(CH2)4NH3]Ln[hedpH][hedpH2] (Ln = Sm (1), Gd (2), Dy (3); hedp = 1-hydroxyethylidenediphosphonate), have been synthesized by hydrothermal reaction with 1,4-diaminobutane as the template and characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. The vertex-sharing connections of the LnO7 polyhedra and CPO3 tetrahedra result in an infinite chain along the b axis. The chains are cross-linked by hydrogen bonds to form a three-dimensional network with channels containing the [NH3(CH2)4NH3]2+ cations.