This work is dedicated to the growth process and investigation of luminescent and scintillation properties of CeAlO₃ single crystals and CeAlO₃/CeAl₁₁O₁₈ metamaterials under e-beam and α-particles excitation. It has been shown that cathodoluminescence and radioluminescence spectra of CeAlO₃ crystals contain two bands, peaking at 440 and 500 nm, and caused by the Ce³⁺ 5d–4f transitions into CeAl₁₁O₁₈ phase, which is present in these crystals as an admixture. Under 270 nm ultraviolet (UV) light excitation, a CeAlO₃ crystal possesses complicated non-exponential luminescence decay, with the average decay time of 16 ns. The light yield of CeAlO₃ crystals under α-particle excitation is about 16% and 12%, in respect to the standard Bi₄Ge₃O₁₂ (BGO) crystal and Y₃Al₅O₁₂:Ce (YAG:Ce) single crystalline film samples, respectively. The CeAlO₃ scintillation decay is quite fast, with the decay time value t_1/e in the 54–56 ns range.

The known metal–C₂O₄ structures may be divided into two modifications, α and β. The α-modification has an order–disorder struxture, revealing one-dimensional disordering of the metal–oxalate chains, and the β-modification is ordered. The crystal structures of orthorhombic γ-MnC₂O₄ {poly[μ-oxalato-manganese(II)]; space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) Å, V = 378.19 (1) ų, Z = 4 and D_x = 2.511 Mg m⁻³} and γ-CdC₂O₄ {poly[μ-oxalato-cadmium(II)]; space group Pmna, a = 7.3218 (1), b = 6.0231 (1), c = 9.2546 (2) Å, V = 408.13 (1) ų, Z = 4 and D_x = 3.262 Mg m⁻³} have been obtained from powder diffraction patterns. The structures are isostructural. Each metal atom in each structure is coordinated by seven O atoms which belong to five oxalate ions. The crystal packing, which contains noticeable cavities in the [101] and [001] directions, is not close packed and essentially differs from the known disordered α- and ordered β-modifications of transition metal oxalates. This modification seems to be metastable. It was found that a spontaneous γ→β phase transition takes place for γ-CdC₂O₄.