2D super(31)P solid state NMR spectroscopy, electronic structure and thermochemistry of PbP sub(7)

Phase pure polycrystalline PbP sub(7) was prepared from the elements via a lead flux. Crystalline pieces with edge-lengths up to 1 mm were obtained. The assignment of the previously published super(31)P solid state NMR spectrum to the seven distinct crystallographic sites was accomplished by radio-frequency driven dipolar recoupling (RFDR) experiments. As commonly found in other solid polyphosphides there is no obvious correlation between the super(31)P chemical shift and structural parameters. PbP sub(7) decomposes incongruently under release of phosphorus forming liquid lead as remainder. The thermal decomposition starts at T>550 K with a vapor pressure almost similar to that of red phosphorus. Electronic structure calculations reveal PbP sub(7) as a semiconductor according to the Zintl description and clearly shows the stereo-active Pb-6s super(2) lone pairs in the electron localization function ELF. Coordination of the lead atoms in PbP sub(7).