NEW TETRAPNICTIDOTITANATES(IV) - NA3M3[TI X4] WITH M = NA SR, NA/EU AND X = P, AS/

The four novel tetrapnictidotitanates(IV) Na4Sr2TiP4, Na4Sr2TiAs4, Na4 .3Eu1.7TiP4 and Na4.3Eu1.7TiAs4 were prepared from the binary pnictide s NaX, M3X, M'X (X=P, As and M'=Sr, Eu) and elementary titanium in tan talum ampoules. The air and moisture sensitive transition metal compou nds form dark red hexagonal crystals. They are semiconductors with E-g =1.8 eV (Sr) and E-g=1.3 eV (Eu), respectively. The compounds are isot ypic with Na6ZnO4 (space group P6(3)mc (no.186); hP22; Z=2; Na4Sr2TiP4 :a=936.8(1) pm, c=740.5(1) pm; Na4Sr2TiAs4: a=958.2(1) pm, c=757.1(1) pm; Na4.3EU1.7TiP4: a=929.9(2) pm, c=732.0(2) pm; Na4.3EU1.7TiCs4: a=9 53.9(1)pm, c=749.5(1)pm). Main structural units are polar oriented [Ti P4](8-) and [TiAs4](8-) tetrahedral anions with (d) over bar(Ti-P)=240 .2(3) pm and (d) over bar(Ti-As)=248.6(3) pm.