This work is dedicated to investigation of new disordered bismuth-containing oxy-phosphates compounds with an original structure type. As previously observed in this series, they are formed of [M 4Bi 2 n −2O 2 n ] x + polycationic ribbons of width n O(Bi,M) 4 tetrahedra, surrounded by PO 4 groups. In the new crystal structure type, double (= D), triple (= T) and tunnels (= t) alternate along a common axis obeying the TtDtTtDt / TTtTTt sequence in respect to a nomenclature previously described and recalled in this work. The existence this new polymorph has first been detected by electron diffraction in a multi-phased sample. Then, the crystal structure type, i.e., the TtDtTtDt / TTtTTt sequence, has been deduced from HREM images help to a contrast-interpreting code available for these series of polycations-formed compounds. The subsequent compounds formulation leads to a number of new materials that verify the general formula: [Bi 2(Bi, M) 4O 4] 2 [Bi 4(Bi, M) 4O 6] 6 (PO 4) 28 M x , with x ⩽ 12 and M=Cu 2+, Cd 2+ cations. Single crystals of the nominal [O6Bi 4.57Cd 3.43] 4 +8.57 [O 6Bi 4Cd 4] 2 +8 [O 4Bi 2Cd 3.56Cu 0.44] 2 +6 (PO 4) 28 Cu 10.86 have been prepared in a further stage and confirms the predicted crystal structure, Bi ∼3.785Cd ∼3.575Cu ∼1.5(PO 4) 3.5O 5.5, a = 11.506 ( 8 ) Å , b = 5.416 ( 4 ) Å , c = 53.94 (4) Å, β = 90 .10(1)°, R F = 0.0835 , R wF = 0.0993 , SG= A 2 / m , Z=8. As already observed for other elements of this family such as Bi ∼1.2 M ∼1.2O 1.5(PO 4), Bi ∼6.2Cu ∼6.2O 8(PO 4) 5 or Bi ∼3Cd ∼3.72 M ∼1.28O 5(PO 4) 3 ( M=Cu, Co, Zn), this compound shows an additional example of PO 4 disorder due to the presence of mixed Bi 3+/M 2+ sites at the edges of ribbons. The origin and consequence of this so-called disorder mostly occurring on PO 4 configurations is intensively discussed and has been characterized by infrared spectroscopy and by neutron diffraction on similar compounds. It is noticeable that the great number of antagonist PO 4 configurations may order along the b-axis within a large periodicity which involves incommensurate lattice.