The crystal structure of rhenium diboride

Abstract

The crystal structure of ReB 2 has been determined from powder data. The unit cell is hexagonal; a=2.900 and c=7.478 A; there are two ReB 2 units per unit cell. The structure may be described in terms of alternating layers of rhenium and boron atoms; the former are planar, the latter are puckered. The two boron atoms show up clearly in difference maps (@z, 2x, Zobs. --@z, 2x, ZRe)" B-B bond lengths are 1.82 ~; shortest Re-B distance are 2.23 and 2.26 A.

Advancements in the Search for Superhard Ultra‐Incompressible Metal Borides

“…Rhenium diboride, originally synthesized in 1962, has the highest B:Re ratio among the known rhenium boride phases-Re 3 B, Re 7 B 3 and ReB 2 -and is therefore the most likely candidate for improving on the mechanical properties of OsB 2 . [60] Ideally, a rhenium compound that is more boron rich, such as the theoretical compound ReB 4 , would be a preferred material using the rationale that a higher boron concentration results in a greater degree of covalent bonding, and thus a harder material. However, since no such compounds are known to exist, ReB 2 remains the best choice.…”

Is Rhenium Diboride a Superhard Material?

“…The densities of the sintered bodies were obtained by the Archimedes method, which gives a value of 12.0 AE 0.3 g cm À3 , 95% of the calculated density. [18] These materials were then examined by Hv measurement and ultrasonic measurement. Hv measurements were performed on these polished compacts by means of a Vickers indentation method using a pyramidal diamond indenter.…”

Comment on "Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure"

“…It is not a novel material, and its previous development and discovery was not discussed in the Chung et al article with sufficient emphasis, especially given that one of the three synthesis methods they reported is extremely similar to that used by LaPlaca and Post (2).…”