In the Bi2O3-MO-P2O5 diagram, on the basis of previous compounds based on 2D-ribbon like units, we have predicted and prepared the infinite term. It contains [Bi2O2]2+ planes arranged within a never-observed crystallographic form. In this series, the ribbons-like units are polycations built on the linkage of n O(Bi,M)4 tetrahedra along their width and infinite in a perpendicular dimension. Hence, this novel form completes the continuous series of analogue compounds, whose building units now extend from the single chain to the infinite plane, via a number of discrete n values (2,3,4,5,6,7,8,9,10,11). The presented materials of formulae Bi4MP2O12 (M= Zn and Mg) roughly show the same crystal structure. However different arrangements of the groups located between the [Bi2O2]2+ planes are at the origin of a complex superstructure in the case of the zinc compounds.