Osmium borides

Their most remarkable property is potentially high hardness.

It is thought that a combination of high electron density of osmium with the strength of boron-osmium covalent bonds will make osmium borides superhard materials, however this has not been demonstrated yet.

Synthesis occurs at high temperatures (~1000 °C) from a mixture of MgB2 and OsCl3.

Osmium diboride was first also sought as hexagonal,[3] but one of its phases was later reassigned to orthorhombic.

[1][4] In recent methods of synthesis, it has also been found that a hexagonal phase of OsB2 exists with a similar structure to ReB2.