the literature data on the region at about 55–60 at.% Cu in the Cu–In phase diagram is somewhat confusing. With Cu10In7 and Cu11In9, two intermetallic compounds have been reported whose structures are alike and both are reported to be stable over a similar temperature range. Here, we show that Cu10In7 can be synthesized and characterized in agreement with the study by Piao and Lidin. Moreover, thermoanalytic methods (TA) reveal that Cu11In9, ht-Cu7In4 (A-phase) and In are formed upon cooling after re-melting of Cu10In7 without further heat treatments. For comparison, Cu11In9 has been synthesized using the original method by Rajasekharan and Schubert. Applying the same TA program to Cu11In9 the result from Cu10In7 was reproduced. Single crystal X-ray diffraction experiments prove that the re