RE2SiO5

RE2SiO5 refers to a family of inorganic compounds in which two trivalent rare-earth elements (RE) are combined with silicon and oxygen in a silicate lattice, giving the general formula RE2SiO5. The RE element can be any trivalent rare-earth, including yttrium; common members include Y2SiO5, La2SiO5, Ce2SiO5, Nd2SiO5, Gd2SiO5, and Er2SiO5. These materials are typically prepared by high-temperature solid-state synthesis from RE2O3 and SiO2, or by solution-based methods that yield powders or single crystals.

Crystal structure and polymorphism: RE2SiO5 compounds can crystallize in monoclinic or orthorhombic polymorphs depending on the specific rare-earth element and synthesis conditions. The prototype Y2SiO5 has a silicate backbone formed by SiO4 tetrahedra and features two distinct rare-earth lattice sites, with the exact coordination environment and space group varying among compositions.

Properties and applications: These materials are generally chemically stable and exhibit wide optical transparency from the visible to near-infrared. When doped with optically active ions (for example Ce3+, Eu3+, or Tb3+), they show luminescence useful for phosphors and scintillators. Ce-doped Y2SiO5 is a well-known fast scintillator used in gamma-ray and medical imaging detectors. Other dopants extend emission ranges and enable laser-host or phosphor applications. RE2SiO5 compounds are also explored as ceramic hosts for high-temperature and structural applications.

See also: rare-earth silicates, Ln2SiO5, Y2SiO5, Ce:Y2SiO5.