The binary bismuth-rhodium (Bi-Rh) phase diagram was reinvestigated from 23 to 60 at.% Rh with focus on the BiRh phase, applying powder-x-ray diffraction (XRD), high temperature powder-XRD, differential thermal analyses and scanning electron microscopy. The phase boundaries of the BiRh phase at 750 °C and the temperature of its peritectic decomposition were refined. In addition, the existence of the two phases Bi 4 Rh and Bi 2 Rh (in two modifications depending on temperature) could be confirmed. Most of the reaction temperatures reported in the literature could be verified within a range of about ± 10 °C. Nevertheless, a few temperatures had to be revised, such as those of the peritectic reactions L + Rh ⇌ BiRh at 979 °C and L + BiRh ⇌ β -Bi 2 Rh at 785 °C. No evidence could be found for the presence of a stable Bi 3 Rh phase in well annealed samples; from the present results it must be concluded that Bi 3 Rh is actually metastable. On the other hand, a new orthorhombic phase BiRh 0.81 was discovered which crystallizes in the MnP structure type (Pmna). It was found that the temperatures of the transition between the low-temperature modification α -Bi 2 Rh and its high-temperature form β -Bi 2 Rh depend considerably on the presence or absence of metastable Bi 3 Rh and stable BiRh 0.81 , respectively., (© The Author(s) 2017.)