Neutron diffraction and observation of superconductivity for tungsten borides, WB and W2B4

Tungsten borides are known to be very hard and metallic materials. Tungsten monoboride, WB, becomes superconducting at Tc = 4.3 K in the tetragonal modification and Tc = 2.8 K in the orthorhombic modification. The structures of the two WB modifications were revised based on X-ray and neutron powder diffraction. W2B4, formerly known as W2B5, also shows a superconducting transition at 5.4 K, which is suppressed for small grain samples.

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