Vibrational spectra and structural considerations of compounds NaLnTiO4

Abstract

The Raman and infrared spectra of compounds NaLnTiO4 (Ln = lanthanide, including yttrium) are reported and discussed. Their most striking feature is a strong band in both spectra at about 900 cm−1. This band is ascribed to a vibration localized in the Ti---O bond directed towards the Na---O layers. The relevant oxygen anion is very poorly charge compensated, and the Ti---O bond is, therefore, very strong. Pauling's electrostatic valence rule appears to be of great use in these considerations. These compounds do not show ferroelectricity.