New Orthorhombic Phase in the Ru–B and Os–B Systems

Abstract

By the use of single crystal and polycrystalline x-ray diffraction techniques, isomorphous orthorhombic lattices (space group No. 59) have been found in the Ru-B and Os-B systems having lattice parameters of a0=4.6443±0.0003 Å, b0=2.8668±0.0008 Å, c0=4.0449±0.0004 Å and a0=4.6832±0.0001 Å, b0=2.8717±0.0002 Å, c0=4.0761±0.0001 Å, respectively. The probable empirical formulas are RuB2 and OsB2, with two formula weights per unit cell.

Elastic anisotropy of OsB2 and RuB2 from first-principles study

“…It is seen that the calculated lattice parameters a, b and c deviate from the corresponding experimental values within 2%, and within 3% for the calculated density, in excellent agreement with both experimental [6,7] and previous theoretical studies [8][9][10][11]. This demonstrated the reliability of the method.…”

“…Both OsB 2 and RuB 2 form in an orthorhombic lattice (space group Pmmn, No. 59) with two formula units per unit cell, in which two transition metal atoms occupy the 2a Wychoff site and four B atoms hold the 4f positions [6,7] (Fig. 1).…”

Thermodynamic and Electronic Properties of OsB2from First-Principles Calculations

“…The obtained lattice constant, bulk modulus B 0 and its pressure derivative B 0 for the Orth and the Hex structures of OsB 2 at zero pressure are listed in Table I. For the Orth structure of OsB 2 the equilibrium lattice parameters obtained are in good agreement with the experimental data [17,18] and other theoretical results [2,3]. The LDA calculations underestimate the lattice constants, while the GGA calculations overestimate the lattice constants.…”

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

“…The structures of ruthenium, osmium and rhenium diboride have been known since 1962, when Aronsson et al [1] and Roof and Kempter [2] described RuB 2 and OsB 2 , while La Placa and Post published the structure of ReB 2 [3], which had formerly been falsely assigned ("ReB 3 ") [4]. The MB 2 (M = Re, Ru, Os) structures were determined by single-crystal X-ray diffraction.…”