Polyazide Chemistry: Preparation and Characterization of Te(N3)4 and [P(C6H5)4]2[Te(N3)6] and Evidence for [N(CH3)4][Te(N3)5] ( This work was funded by the Defense Advanced Research Projects Agency, with additional support from the Air Force Office of Scientific Research and the National Science Foundation. R.H. thanks the Deutsche Forschungsgemeinschaft for a postdoctoral fellowship. We thank Drs. A. Morrish, D. Woodbury, and M. Berman for their steady support, and Drs. R. Wagner, I. Tsyba, and Prof. R. Bau for their help and stimulating discussions. We also thank Prof. T. Klapötke and his colleagues for exchange of information about their independent syntheses of Te(N3)4 and Te(N3)5-. )