High-pressure synthesis and crystal structure of silicon phosphate hydroxide, SiPO4(OH)

Linda A. Stearns, Thomas L. Groy, Kurt Leinenweber

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


A new high-pressure phase, silicon phosphate hydroxide, was prepared at 8.3±0.5GPa and 1000°C in >98% purity. From X-ray diffraction on a pseudo-merohedrally twinned crystal, it was found that SiPO4(OH) crystallizes in a monoclinic cell with space group P21/n (No. 14), a=6.8446(11)Å,b=6.8683(13)Å,c=6.8446(11)Å,β=119.77(1) °, and Z=4. The refinement gave a conventional Robs of 0.0320 and wRobs of 0.0864 for the overlapped data from both twin components. In the structure, SiO6 octahedra form chains along [101], with PO4 tetrahedra alternating along the chain in the b-direction. The parallel chains link up with tetrahedral corners from other chains to form a 3-dimensional network. SiPO4(OH) belongs to a structural family that includes HgSeO4·H2O. It is also related to the SbOPO4 structure by a small distortion that lowers the symmetry from C2/c in SbOPO4 to P21/c(P21/n) in SiPO4(OH).

Original languageEnglish (US)
Pages (from-to)2594-2601
Number of pages8
JournalJournal of Solid State Chemistry
Issue number9
StatePublished - Sep 2005


  • High-pressure synthesis
  • Pseudo-merohedral twinning
  • Silicon phosphates
  • Six-coordinated silicon

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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