The Crystal Structure of MnB4.

Peierls distortion, magnetism, and high hardness of manganese tetraboride

“…Every column of MnB12 polyhedra is shifted with respect to the four nearest ones over half of the c parameter. Andersson and Carlsson [17] described the structure of MnB 4 as highly similar to that of the orthorhombic CrB 4 (space group Immm) [29] with insignificant differences in the atomic arrangement.…”

“…Based on powder x-ray diffraction data the crystal structure of MnB 4 was initially established as monoclinic [16,17] (space group C2/m). The reported unit cell parameters were a = 5.5029(3), b = 5.3669(3), c = 2.9487(2)Å, β = 122.710(5)°, and the structure was described as a three-dimensional boron network with Mn atoms inside the voids [17].…”

Thermodynamic Assessment of the Mn-B System

“…Although all of these compounds were confirmed to exist, most of the equilibrium data reported by Markovskii and Bezruk [11] were updated by subsequent researchers. [12][13][14][15][16][17][18][19][20][21][22][23] In the following, the phase relationship in the Mn-B phase diagram is critically discussed.…”

“…However, MnB 4 was confirmed to decompose into MnB 2 and b(B) at high temperature. [13,16,17,20,22,23] Andersson and Carlsson [17] reported the decomposition temperature to be between 1350 and 1400°C. In addition, MnB 2 decomposes to Mn 3 B 4 and MnB 4 [13,14,16,17,20,22,23] at lower temperature.…”

“…[13,16,17,20,22,23] Andersson and Carlsson [17] reported the decomposition temperature to be between 1350 and 1400°C. In addition, MnB 2 decomposes to Mn 3 B 4 and MnB 4 [13,14,16,17,20,22,23] at lower temperature. The decomposition temperature determined by Andersson and Carlsson [17] was between 1050 and 1100°C, which was consistent with the result of Cely et al [20] who reported the temperature to be between 1050 and 1150°C.…”