It is one of the fundamental compounds formed in reactions between erbium and boron. The compound is isostructural with all other reported rare earth hexaboride compounds including lanthanum hexaboride, samarium hexaboride, and cerium hexaboride. Due to the isostructural nature of the rare earth hexaborides and the strong interaction of boron octahedra within the crystal, these compounds show a high degree of lattice matching which suggests the possibility of doping by substituting one rare earth metal within the crystal with another. Until recently, it had been hypothesized that erbium hexaboride was unstable due to the small size of the Er3+ cation within the crystal structure when compared to the ionic radii of other rare earth elements which form known rare earth hexaboride compounds. It has now been demonstrated, however, that new nanoscale synthetic methods are capable of producing high purity, stable erbium hexaboride nanowires. These wires, produced using chemical vapor deposition (CVD), have a reported lattice constant of 4.1 Å.
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