Crystalline and vitreous Na3.89Ca0.67Al0.23Ti0.77(PO4)3 : Synthesis, crystal structure, vibrational and UV–Visible spectra

•New NaCaAlTi-Phosphate was synthesized in both crystalline and glassy forms.•The crystalline compound belongs to the Nasicon family.•Its structure consists of a 3D network formed by AO6 (A=Na, Ca, Al, Ti) octahedra and PO4 tetrahedra linked by corners.•The glass structure contains PO4 and P2O7 groups and TiO6 octahedra linked by corners to form short -O-Ti-O-Ti-O- chains. Na3.89Ca0.67Al0.23Ti0.77(PO4)3 phosphate exists in both crystalline and vitreous forms. It has been synthesized as microcrystalline powder, single crystals and glass. The structure of the crystalline form, belonging to Nasicon family with M(1)M(2)3A2(PO4)3 formula, was solved by single crystal X-ray diffraction (Space group R32, Z = 6, ah = 8.9976(1) Å, ch = 21.8312(3) Å, R1 = 0.03, wR2 = 0.06). A Rietveld refinement was also performed. The structure is formed by a 3D network of PO4 tetrahedra and AO6 (A= Na/Ca and Al/Ti) octahedra sharing corners. One of the two positions of A sites is statistically occupied by Na+ and Ca2+, the other position is statistically occupied by Al3+ and Ti4+. The remaining sodium atoms occupy totally M(1) and partially M(2) interstitial sites. Raman and infrared spectra show for the crystalline powder, broad peaks attributed principally to monophosphate PO4 modes. The structure of the glass contains PO4 and P2O7 groups and short -Ti-O-Ti-O- chains. UV–Visible spectra consist of strong bands at high energy assigned to O-Ti and O-Al electronic charge transfers. [Display omitted]