The crystal structure of a Terbium(III) complex with 1,1-Cyclobutanedicarboxylic acid

A complex of 1,1-cyclobutanedicarboxylic acid with terbium was obtained as a pentahydrate. The salt crystallizes in the monoclinic system, space group P2₁/n with a = 15.885(3), b = 8.489(2), c = 19.189(4)?Å, β = 106.02(3)° and Z = 4. The structure was solved by direct methods and refined to R = 0.0537. The complex forms polymeric chains in which terbium(III) ions are linked by carboxylate bridges. Each terbium cation is surrounded by carboxylate oxygen atoms and two or three water oxygen atoms, giving coordination number 9. The structure is stabilized by a system of hydrogen bonds.