3,3′‐Seleno­bis­(propionic acid)

In contrast to Se[CH₂C(O)OH]₂versus S[CH₂C(O)OH]₂, the title compound, Se[CH₂CH₂C(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)° and the Se—C bond lengths are 1.9610 (14) Å. The shortest Se?O intermolecular distance is 3.5410 (11) Å. The O?O distances in the carboxyl­ic acid dimers are 2.684 (2) Å. The temperature dependence of the IR spectrum suggests tautomerism in the solid state.