Metal borides¹ are inorganic solids that often show refractory properties, like super-hardness² and very high-melting points. They may also prove to be exciting concerning their electronic structure, as shown for super-conducting magnesium diboride, MgB₂,³ or samarium hexaboride, SmB₆,⁴ which was recently found to be a topological insulator.

New investigations on nanoscale and bulk mono-, di- tetra-, and hexaborides will be presented. Examples are MnB₄, crystallizing similar to hypothetical tetragonal diamond but exhibiting an unexpected Peierls distortion,^5,6 solid solutions of (M,M')B₆ with good thermoelectric properties,⁷ and nanoscale metal borides that can be (ferro)magnetic.⁸ Synthesis, characterization, structures, and properties will be discussed.
¹ B. Albert, H. Hillebrecht, Angew. Chem. Int. Ed. 48 (2009) 8640-8668² R. Mohammadi, A.T. Lech, M. Xie, B. E. Weaver, M. T. Yeung, S. H. Tolbert, R. B. Kaner, PNAS 108 (2011) 10958-10962³ J. Nagamatsu, N. Nakagawa,T. Muranaka, J. Akimitsu,Y. Zenitani, Nature (2001) 63-64⁴ D. J. Kim, J. Xia, Z. Fisk, Nature Materials 13 (2014) 466-470⁵ A. Knappschneider, C. Litterscheid, N.C. George, J. Brgoch, N. Wagner, J. Beck. J.A. Kurzman, R. Seshadri, B. Albert, Angew. Chem. 126 (2014) 1710-1714, Int. Ed. Engl. 53 (2014) 1684-1688⁶ A. Knappschneider, C. Litterscheid, J. Brgoch, N. C. George, S. Henke, A. K. Cheetham, J. G. Hu, R. Seshadri, B. Albert, Chem. Eur. J. 21 (2015), 8177-8181⁷ M. Gürsoy, M. Takeda, and B. Albert, J. Solid State Chem. 221 (2015) 191-195⁸ S. Rades, S. Kraemer, R. Seshadri, B. Albert, Chem. Mater. (2014) 1549-1552