The molybdenyl compound [NBu₄][MoO₂(C₆F₅)₃] (1) has been obtained by low-temperature treatment of MoO₂Cl₂ with LiC₆F₅ in Et₂O followed by addition of [NBu₄]Br. This compound of the (AO₂X₃)^- type shows an unusual five-coordinate structure not lying on the Berry-pseudorotation path: it can be described rather as an edge-caped tetrahedron (TE-5). The same kind of structure has been found by DFT calculations to be the most energetically favored for the mononuclear (MoO₂X₃)^- model species, where X = H, Cl or CN. The unusual TE-5 structure is rationalized in terms of the electronic structure of the very (MoO₂)²⁺ unit.