Synthesis and crystal structure of Ti12Sn3O10 - a low valent oxide of titanium with an oxidic network and intermetallic "islands"

The new ternary compound Ti12Sn3O10 is obtained by the reaction of Ti, TiO2 and Sn at 1500 degrees C. According to the single crystal structure analys is (cubic. space group Fm3m. a = 13.5652(9)Angstrom, Z = 8, wR(2)(I)= 0.048 , R-1(F) = 0.020) the air stable compound represents a new structure type c ombining structural features of oxides and intermetallics. While tin is sur rounded only by titanium the five different Ti atoms have oxidic and metall ic coordination spheres as well, explaining the quite low averaged oxidatio n number. The crystal structure is characterized by a three-dimensional net of Ti4O-tetrahedra and trigonal bipyramides Ti5O. In the voids there are i ntermetallic "islands" of a composition Ti33Sn6 With a diameter of about 10 Angstrom.