Structural stability and equation of state of thorium carbide for pressures up to 36 GPa

High-pressure X-ray diffraction studies have been performed on ThC powder up to 36 GPa. No structural phase transformation has been observed, the rock-salt structure of ThC being stable over the whole pressure range. The equation of state can be described by the Murnaghan equation with the bulk modulus B₀ = 109(7) GPa and its pressure derivative B'₀ = 3.1(6). The high-pressure behaviour of ThC is compared with that of other actinide carbides and nitrides and correlated with the occupation of the 5f electron shell.