Acta Crystallographica · 1954 · 77 citations · 0 references
Natural SciencesChemistryPhysicsCondensed Matter PhysicsCrystal StructureSolid State PhysicsCrystal LatticeCrystal SymmetryCrystallographic AxesCrystallographyLattice SymmetryUnit CellsCrystal Lattice SymmetryCrystal Structure DeterminationCrystal Symmetry AnalysisCrystallographic SymmetryHexagonal Crystal LatticesLattice ConstantsRhombohedral Unit CellsThreefold Axes
The crystal structure of samarium is rhombohedral; a = 8.996 A, o --23 13', Z = 3. The atomic positions are 0, 0, 0; 3, 3, 3; and ~, ~, ~. Single-crystal data require a disordered (or submicroscopically twinned) structure where half of the unit cells are rotated 180 about the threefold axis with respect to the other half. The hexagonal lattice constants are a ----3.6210.007 A,