Fifteen isostructural rare earth metal squarates incorporating ethylene glycol ligand with the formula RE(C4O4)(1.5)(C2H6O2) (RE = Y, La-Nd, Sm-Lu) have been synthesized under hydrothermal conditions and structurally characterized by single-crystal and powder X-ray diffraction, C-13 CPMAS NMR, absorption spectroscopy, and magnetic susceptibility. A variable-temperature in situ powder X-ray diffraction study on the Ce compound was also performed to determine its thermal stability. Each RE3+ cation in the structure is bonded to six squarate anions and one neutral ethylene glycol chelate, and each C4O42- anion coordinates to four RE3+ cations such that a new 3-D framework is formed. They are the first examples of organic-inorganic hybrids which contain both squarate and ethylene glycol ligands.
