Contribution to the equilibrium phase diagram of the Mn–Bi system near MnBi

The phase diagram of the Mn–Bi system near the compound MnBi was studied with single crystals in the as-grown and heat-treated states. The results show that the high-temperature phase of MnBi is in fact a separate compound with chemical formula Mn1.08Bi, when grown from a Bi-rich solution. It was found that the transformation of MnBi at 355°C upon heating is associated with a peritectic decomposition of MnBi into Mn1.08Bi+liquid, and the transformation at 340°C upon cooling of the high-temperature phase is the result of decomposition of Mn1.08Bi to MnBi±Mn.