A metastable polymorph of Ti3Sn (called c-Ti3Sn) exhibiting the cubic Cr3Si-type structure was prepared by a mechanochemical route. At temperatures of about 450 °C, it transforms to the well-known hexagonal phase (Ni3Sn type, called h-Ti3Sn). 0.5% of iron was incorporated into the material originating from the steel beaker and the steel balls. However, quantum-chemical calculations show that this should not lead to a stabilization of the Cr3Si type. c-Ti3Sn shows a single signal at an isomer shift of