Polymorphy of monoclinic terbium triborate, TbB3O6

✍ Scribed by P. Becker; R. Fröhlich

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 339 KB
• Volume: 43
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.200800397

✦ Synopsis

TbB 3 O 6 , that suffers peritectic decomposition below its melting point, was obtained as single crystals by growth from borate flux. Depending on the borate flux, orthorhombic (space group Pnma) TbB 3 O 6 belonging to the isomorphic series of rare earth triborates with small lanthanides, or monoclinic (space group C2/c) TbB 3 O 6 , belonging the corresponding isomorphic series with large lanthanides, was synthesized. Within a broad range at subambient temperatures monoclinic TbB 3 O 6 shows a structural phase transition with a large thermal hysteresis. The phase transition was characterised by means of differential scanning calorimetry, temperature-dependent polarization microscopy and single-crystal X-ray diffraction. According to the observed features the transition can be classified as a non-ferroic, martensitic phase transformation.