3,3'-Selenobis(propionic acid)

In contrast to Se[CH2C(O)OH]2 versus S[CH2C(O)OH](2), the title compound, Se[CH(2)CH(2)C(O)OH]2 or C6H10O4Se, is structurally quite similar to its sulfur analogue. The molecule has twofold symmetry. The C-Se-C bond angle is 96.48 (8) degrees and the Se-C bond lengths are 1.9610 (14) Å. The shortest SeO intermolecular distance is 3.5410 (11) Å. The OO distances in the carboxylic acid dimers are 2.684 (2) Å. The temperature dependence of the IR spectrum suggests tautomerism in the solid state. Formula: C6H10O4S