Cs4P2Se10: A new compound discovered with the application of solid-state and high temperature NMR

The new compound Cs4P2Se10 was serendipitously produced in high purity during a high-temperature synthesis done in a nuclear magnetic resonance (NMR) spectrometer. P magic angle spinning (MAS) NMR of the products of the synthesis revealed that the dominant phosphorus-containing product had a chemical shift of 52.8 ppm that could not be assigned to any known compound. Deep reddish brown well-formed plate-like crystals were isolated from the NMR reaction ampoule and the structure was solved with X-ray diffraction. Cs4P2Se10 has the triclinic space group P-1 with a 1⁄4 7.3587(11) Å, b 1⁄4 7.4546(11) Å, c 1⁄4 10.1420(15) Å, a 1⁄4 85.938(2)1, b 1⁄4 88.055(2)1, and g 1⁄4 85.609(2)1 and contains the [P2Se10] anion. To our knowledge, this is the first compound containing this anion that is composed of two tetrahedral (PSe4) units connected by a diselenide linkage. It was also possible to form a glass by quenching the melt in ice water, and Cs4P2Se10 was recovered upon annealing. The static P NMR spectrum at 350 1C contained a single peak with a 35 ppm chemical shift and a 7 ppm peak width. This study highlights the potential of solid-state and high-temperature NMR for aiding discovery of new compounds and for probing the species that exist at high temperature. r 2007 Elsevier Inc. All rights reserved.