M₂B₅ or M₂B₄? A Reinvestigation of the Mo/B and W/B System

Abstract

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Crystal Structures of the Metal Diborides ReB2, RuB2, and OsB2 from Neutron Powder Diffraction

“…Rietveld a) Maximum residual electron density is found at the origin of the cell, but residual neutron scattering is very low at that position. [29], which are even more similar to ReB 2 . Their crystal structures again consist of alternating layers of metal and boron atoms, hence the boron atom layers are alternating planar (as in AlB 2 ) or corrugated (as in ReB 2 ).…”

Rediscovering the Crystal Chemistry of Borides

“…ReB 2(hex) (Figure 8), W 2 B 4(hex) ("W 2 B 5(hex) "; note that while the structure is referred to as having a "W 2 B 5(hex) " structure, it has been shown more recently that the stoichiometry is W 2 B 4; [177] Figure 10) are similar to the AlB 2 structure and have either regular or deformed two-dimensional boron layers. W 2 B 4(hex) (previously "W 2 B 5(hex) ") and Mo 2 B 4(rhomb) (previously "Mo 2 B 5(rhomb) ") differ in the alternation order of metal layers.…”

“…[173] Note that while the structure is referred to as having a "W 2 B 5(hex) " structure, it has been shown recently that the stoicheometry is W 2 B 4 . [177] Boron atoms are in gray, metal atoms are in dark gray. Figure 10.…”

Enthalpies of Formation of Transition Metal Diborides: A First Principles Study

“…This last structure has been included because first principles calculations have shown that this structure could be stable at high pressure in the cases of TiB 2 [3] and MoB 2 [4] compounds. The characteristics of the structures considered in the present work are given in Table 1 [5][6][7][8][9][10][11][12][13]. [14].…”