Lanthanum tetraboride
| Identifiers | |
|---|---|
3D model (JSmol) |
|
| |
| |
| Properties | |
| B4La | |
| Molar mass | 182.15 g·mol−1 |
| Appearance | gray to black crystalline solid |
| Density | 5.396 g/cm3 |
| Melting point | 2,210 °C (4,010 °F; 2,480 K) |
| Structure[1] | |
| tetragonal | |
| P4/mbm | |
a = 7.324 Å, b = 7.324 Å, c = 4.181 Å | |
Formula units (Z) |
4 units per cell |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
Lanthanum tetraboride is a binary inorganic compound of lanthanum and boron with the chemical formula LaB4. The compound forms a gray to black crystalline solid and demonstrates metallic conductivity.[2]
Properties
Lanthanum tetraboride is a refractory, high-hardness inorganic compound crystallizing in the tetragonal crystal system, space group P4/mbm.[1] The arrangement of atoms is the same as in the tetraborides of cerium, thorium and uranium (CeB4, ThB4, UB4)[1] LaB4 is distinct from the more common lanthanum hexaboride LaB6 but shares high-temperature stability, with its boron sublattices containing structural elements of both diborides and hexaborides.[3] The compound undergoes a series of phase transitions under high pressure.[4]
Synthesis
Lanthanum tetraboride can be prepared by the reduction of lanthanum oxide by boron carbide under vacuum:[5]
- La2O3 + 2 B4C + С → 2 LaB4 + 3 CO
Another method involves heating lanthanum metal and boron at 1300 °C under vacuum.[6]
Uses
The compound is generally a subject of materials science research.[3] Also it is especially suitable for high-temperature applications.
References
- 1 2 3 Kato, K.; Kawada, I.; Oshima, C.; Kawai, S. (15 December 1974). "Lanthanum tetraboride". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 30 (12): 2933–2934. Bibcode:1974AcCrB..30.2933K. doi:10.1107/S0567740874008570. ISSN 0567-7408. Retrieved 6 May 2026.
- ↑ "Lanthanum boride: General information". materials.springer.com. Retrieved 6 May 2026.
- 1 2 Surucu, G.; Ozısık, H.; Deligoz, E.; Shein, I. R.; Matovnikov, A. V.; Mitroshenkov, N. V.; Morozov, A. V.; Novikov, V. V. (5 May 2021). "Electronic and thermodynamic properties of lanthanum tetraboride on low-temperature experimental and ab-initio calculation data". Journal of Alloys and Compounds. 862 158020. doi:10.1016/j.jallcom.2020.158020. ISSN 0925-8388. Retrieved 6 May 2026.
- ↑ Pan, Chen; Wang, Sheng-Yan; Tang, Hui; Wu, Hong-Yun; Shi, Guo-Yong; Cao, Kun; Jiang, Hong; Su, Yue-Hua; Zhang, Chao (1 May 2022). "Phase transition and enhanced hardness of LaB4 under pressure". Journal of Physics and Chemistry of Solids. 164 110622. arXiv:2112.00251. Bibcode:2022JPCS..16410622P. doi:10.1016/j.jpcs.2022.110622. ISSN 0022-3697. Retrieved 6 May 2026.
- ↑ Samsonov, G. V. (22 October 2013). Refractory Transition Metal Compounds: High Temperature Cermets. Elsevier. p. 143. ISBN 978-1-4832-7083-8. Retrieved 6 May 2026.
- ↑ Felten, Edward J.; Binder, Ira; Post, Ben (1 July 1958). "Europium Hexaboride and Lanthanum Tetraboride". Journal of the American Chemical Society. 80 (13): 3479. Bibcode:1958JAChS..80Q3479F. doi:10.1021/ja01546a069. ISSN 0002-7863. Retrieved 6 May 2026.
Further reading
- Bolgar, A. S.; Muratov, V. B.; Meleshevich, K. A.; Khorpyakov, O. T. (1 November 1990). "Thermodynamic parameters for lanthanum tetraboride over a wide temperature range". Soviet Powder Metallurgy and Metal Ceramics. 29 (11): 917–920. doi:10.1007/BF00794028. ISSN 1573-9066. Retrieved 6 May 2026.