Table 1.
Unit cell demensions of rhombohedral phases formed in Bi2O3 systems
| Oxide addition | Starting composition | Final heat treatment | Additional phases present | Ionic radius of cation (Ahrens) | Unit cell dimensions
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| Hexagonal | Rhombohedral | ||||||||
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| °C/hr | a | c | c/a | a | α | ||||
| A | A | A | |||||||
| CaOa | 6Bi2O3:CaO | 700°/107 | None | 0.99 | 3.941 | 27.95 | 7.09 | 9.590 | 23°44′ |
| SrOa,b | 19Bi2O3:2SrO | 699°/144 | Mon Bi2O3 (moderate) | 1.12 | 3.952 | 28.09 | 7.11 | 9.637 | 23°40′ |
| BaOa | 6Bi2O3:BaO | 700°/107 | b.c.c. Bi2O3 (small) | 1.34 | 3.972 | 28.54 | 7.185 | 9.786 | 23°26′ |
| Sm2O3 | 12Bi2O3:Sm2O3 | 700°/107 | tr? | 1.00 | 3.950 | 27.93 | 7.07 | 9.585 | 23°46′ |
| La2O3 | 12Bi2O3: La2O3 | 700°/107 | b.c.c. Bi2O3 (moderate) | 1.14 | 3.975 | 28.10 | 7.07 | 9.644 | 23°48′ |