Experimental Crystal data

R factor = 0.037; wR factor = 0.097; data-to-parameter ratio = 16.4. Single crystals of Pr5Si3N9, pentapraseodymium trisilicon nonanitride, were obtained by the reaction of elemental praseodymium with silicon diimide in a radio-frequency furnace at 1873 K. The crystal structure consists of a chain-like Si—N substructure of corner-sharing SiN4 tetrahedra. An additional Q1-type [SiN4] unit is attached to every second tetrahedron directed alternately in opposite directions. The resulting branched chains interlock with each other, building up a three-dimensional structure. The central atoms of the Q1-type [SiN4] unit and of its attached tetrahedron are situated on a mirror plane, as are two of the four crystallographically unique Pr3+ ions. The latter are coordinated by six to ten N atoms, with Pr—N distances similar to those of other rare earth nitridosilicates. Related literature For isotypic compounds Ln5Si3N9 (Ln = La, Ce), see: Schmolke et al. (2009). For experimental details, see: Schnick & Huppertz (1997); Schnick et al. (1999). Typical atomic distances for rare earth nitridosilicates have been reported b