The actual structure of the vanadium phosphate K 6 (VO) 2 (V 2 O 3 ) 2 (PO 4 ) 4 (P 2 O 7 ) has been determined, using a much larger single crystal than previously used for the isostructural Rb-phase. The actual supercell is four times larger than the corresponding orthorhombic subcell with a=26.777Å, b=28.480Å, c=6.972Å, α=β=γ=90°. The structure resolution, performed in the triclinic space group C-1, shows that the P 2 O 7 groups alone are responsible for the superstructure, all the other atoms keeping the atomic positions of the orthorhombic subcell. This structural study shows a perfect ordering of the P 2 O 7 groups in the actual structure, in contrast to the results obtained from the subcell. Concomitantly, the V 4+ and V 5+ are found to be ordered in the form of [110] stripes.