Ti5Si1.3Sb1.7 - The first titanium silicide antimonide, forming a crystal structure not found in either binary system

Ti5SixSb3-x can be prepared by melting mixtures of Ti, Si, and TiSb2. The t ernary phase with x = 1.32(5) crystallizes in the W5Si3 type (space group I 4/mcm, Z = 8, for x = 1.32(5): a = 1034.6(2), c = 515.2(1) pm), while Ti5Sb 3 and Ti5Si3 adopt the Yb5Sb3 type and the Mn5Si3 type, respectively. The S i and Sb atoms share two sites in Ti5Si1.32(5)Sb1.68: one site is located w ithin a linear chain with short interatomic bonds, which is almost exclusiv ely occupied by Si (i.e., 92(1)% Si and 8% Sb), whereas the second site, be ing occupied by 80(2)% Sb and 20% Si, shows no significant interactions bet ween the main group elements. Band structure calculations reveal the new si licide antimonide being metallic as a consequence of partly filled Ti d sta tes. The structure is mainly stabilized by bonding Ti-Sb, Ti-Si, and Si-Si interactions.