Neutron scattering experiments under magnetic field and under high pressure reveal that the unusual properties of the low carrier system CeP originate from the appearance of Γ8,–like Ce ions, the moment value of which is about 2μBamong Ce ions with Γ7crystal field ground state. The 2μBCe ions appear periodically in the form of double layers of (001) plane in which the Ceions couple together ferromagnetically. The formation of a lattice of 2μBCe ions with a systematic change of the period under the external fields, and the coexistence of antiferromagnetism in the γ7Ce lattice, which is sandwiched by the 2μBCe layers, characterize the complex phase diagrams of CeP.