Structure of a new form of silicon phosphate (SiP 2O 7) synthesized at high pressures and temperatures

Kurt Leinenweber, Linda A. Stearns, Jacob M. Nite, Péter Németh, Thomas L. Groy

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


A new high-pressure phase of SiP 2O 7 has been found and its crystal structure solved and refined from a single crystal grown at a condition of 16 GPa and 2000 °C and recovered to ambient conditions. The material is monoclinic, with the space group P2 1/c and lattice parameters a=4.3042(7) Å, b=7.1505(12) Å, c=6.2897(11) Å, β=103.805(2). The structure contains SiO 6 octahedra in a corner-sharing arrangement with P 2O 7 dimers, the same structural elements and vertex-sharing present in all the low-pressure forms of SiP 2O 7. However, the network is more condensed: the topology of the packing of SiO 6 octahedra and P 2O 7 dimers (represented by Si and the bridging oxygen that both lie on centers of symmetry) is that of the CsCl structure, with some distortion. The resulting phase is 11.2% to 22.3% denser than the various low-pressure forms of SiP 2O 7. The structural data indicates that the P 2O 7 dimers are linear (P-O-P angle=180°), an unusual feature for phosphates.

Original languageEnglish (US)
Pages (from-to)221-225
Number of pages5
JournalJournal of Solid State Chemistry
StatePublished - Jun 1 2012


  • Crystal structur
  • High pressure
  • Phosphates
  • Silicon phosphate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


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