Tris(4-formyl­phen­yl)phosphane oxide tetra­hydro­furan hemisolvate

The title compound, C₂₁H₁₅O₄P·0.5C₄H₈O, contains an ordered phosphane oxide in a general position and a tetra­hydro­furan solvent mol­ecule disordered about a twofold axis. All three aldehyde substituents are nearly coplanar with their attached benzene rings, with C—C—C—O torsion angles in the range 1.64 (17)–4.24 (19)°. All three have different conformations with respect to the P=O group, one syn, one anti, and one gauche. Two of the aldehyde substituents form inter­molecular C—H...O contacts.