α-Ti(HPO4)2·H2O (α-TiP) [1] and its propylamine intercalation product, αTi(HPO4)2·2C3H7NH2·H2O (α-TiPPr) [2], have been previously both synthesized and characterized. On the other hand, Eu3+ is often considered as a chemical analogue for trivalent heavy metals, lanthanides and also actinides (such as Np, Am, Cm and Pu, radionuclides found in high-level radioactive waste produced during the nuclear fuel cycle) [3]. In this way, in our Lab, the sorption capacity for europium(III) of layered titanium(IV) phosphates was investigated, and this purpose was accomplished by treating α-TiP and α-TiPPr with europium(III) nitrate solutions at different concentrations until the equilibrium is reached [4]. All samples were characterized, among others, by powder X-ray diffraction (PXRD), scanning and transmission electron microscopies (SEM, TEM, STEM-EDX, SAED), thermogravimetric analysis (TGA), and photoluminescence (PL) measurements. The results show that the Eu3+ uptake is limited to surface when α-TiP is used as sorbent. Nevertheless, the Eu-retention is considerably enhanced with α-TiPPr as a consequence of an ion-exchange process into the interlayer space of the layered titanium phosphate (involving propylammonium cations, C3H7NH3+, and hexahydrate europium(III) species, [Eu(H2O)6]3+), and the crystal structure of a hypothetical final product, α-[Eu(H2O)6]2/3Ti(PO4)2·[(H2O)6]1/3, has been proposed by using DFT calculations. This contribution reports the solid-state-NMR characterization (1H, 14C, and 31P) of the three aforementioned compounds (α-Ti(HPO4)2·H2O, α-Ti(HPO4)2·2C3H7NH2·H2O, and α[Eu(H2O)6]2/3Ti(PO4)2·[(H2O)6]1/3), and the description of the kinetic features for their thermooxidative decomposition processes.