In Ti2FeNiSb2 double half-Heusler alloys, Sb is in a -3 ionic state. If we doped by Bi(-3) ion, there might be a chance of replacing the Sb(-3). For this purpose, I would like to know the ionic size of Sb(-3) and Bi(-3). I searched in the literature but never found it there. I will deeply appreciate it if somebody let me know this.