We elaborated the identification technique for X-ray powder diffractionby means of X-ray diffractometry, chromatography, and high-temperature X-ray powder diffraction. We take into consideration the nature of mixtures (isomorphic or mechanic); features of molecule packing in the structure of a multi-component solid solution (orthorhombic character of the elementary cell and its frequent super-periodicity along the axis c); and diversity of the phase states of a solid solution (crystal state cryst and rotator-crystal states: low-temperature rot.1, intermediate rot.1+2, and high-temperature rot.2). The investigations were carried out in connection with a determination of forms of natural normal paraffins CnH2n+2 (solid solutions, mechanic mixtures, other compositions) and use them as a basis for elaboration of different composition materials