On polymorphism and morphotropism of rare earth sesquioxides

  title={On polymorphism and morphotropism of rare earth sesquioxides},
  author={Pavel P. Fedorov and Mikhail V. Nazarkin and R. M. Zakalyukin},
  journal={Crystallography Reports},
The data on the phase transitions in the series of rare earth sesquioxides are considered in terms of the thermodynamic theory of morphotropism. It is shown that the scheme of polymorphism and morphotropism suggested by V.V. Glushkova is the most adequate. The derivatographic dehydration of lanthanum and neodymium oxide hydrates is performed. The transition of the cubic C modification into the hexagonal A modification of neodymium oxide is accompanied by the removal of volatile impurities and… 
Morphotropism of Rare-Earth Orthoborates RBO3
  • P. Fedorov
  • Geology, Materials Science
    Journal of Structural Chemistry
  • 2019
A diagram in the coordinates “temperature-ionic radius” is built for polymorphic and morphotropic transitions in a series of REE orthoborates. The stability fields are determined for the structural
Thermochemistry of Lanthana- and Yttria- Doped Thoria
Lanthanide-doped thoria is relevant both to nuclear energy and to solid oxide fuel cell technology. It is also a simple model system in which oxygen vacancy concentration is directly proportional to
Phase stability study of the pseudobinary system Gd2O3-Nd2O3 (T≙1350°C)
The phase stability of the system Gd2O3-Nd2O3 up to 1350°C was studied. Mixed oxides were synthesized by coprecipitation of mixed oxalates. Depending on the thermal treatment, three possible
Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study
Raman spectra of R2O3 (R—Sc, Er, Y, Ho, Gd, Eu, and Sm) powders with C-type bixbyite crystal structure are measured. With the help of these data and ones, previously published for other oxides from
The role of REE in the crystallization of lanthanites
The formation of crystalline rare earth element (REE) (e.g. La, Ce, Pr, Nd) carbonates from aqueous solutions was examined at ambient temperature using UV-Vis spectrophotometry, combined with X-ray
The role of REE3+ in the crystallization of lanthanites
Abstract The formation of crystalline rare earth element (REE) (e.g. La, Ce, Pr, Nd) carbonates from aqueous solutions was examined at ambient temperature using UV-Vis spectrophotometry, combined


Under equilibrium conditions the polymorphic forms of the rare earth sesquioxides transform reversibly from onen form to the other. The sesquioxides of the largest ions, La, Ce, and Pr, exhibit the
Crystallographic shear relations between the structure types α‐UO3, CaF2, La2O3 and NaCl and a correlation of some lanthanide and actinide oxide structures
  • B. Hyde
  • Materials Science, Chemistry
  • 1971
When the α-UO3, La2O3 and NaCl structure types are idealized by a topological distortion involving only an extension or contraction of the hexagonal c axis (cubic [111]) it is clear that they are
Beiträge zur Polymorphie der Sesquioxide der Seltenen Erden
An den Sesquioxiden von Samarium, Europium und Gadolinium wird die Umwandlung von Modifikation C in Modifikation B untersucht. Die Minimaltemperatur fur den Umwandlungsbeginn und die Geschwindigkeit
Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides
The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations. Revisions are based on new structural data,