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Title: Structure of a new form of silicon phosphate (SiP{sub 2}O{sub 7}) synthesized at high pressures and temperatures

Abstract

A new high-pressure phase of SiP{sub 2}O{sub 7} has been found and its crystal structure solved and refined from a single crystal grown at a condition of 16 GPa and 2000 Degree-Sign C and recovered to ambient conditions. The material is monoclinic, with the space group P2{sub 1}/c and lattice parameters a=4.3042(7) A, b=7.1505(12) A, c=6.2897(11) A, {beta}=103.805(2). The structure contains SiO{sub 6} octahedra in a corner-sharing arrangement with P{sub 2}O{sub 7} dimers, the same structural elements and vertex-sharing present in all the low-pressure forms of SiP{sub 2}O{sub 7}. However, the network is more condensed: the topology of the packing of SiO{sub 6} octahedra and P{sub 2}O{sub 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{sub 2}O{sub 7}. The structural data indicates that the P{sub 2}O{sub 7} dimers are linear (P-O-P angle=180 Degree-Sign ), an unusual feature for phosphates. - Graphical abstract: Single crystals of a new form of SiP{sub 2}O{sub 7} were synthesized at high pressure and temperature and the structure solved. Left: the high pressure multi-anvil assemblymore » in a nest of 25.4 mm carbide anvil cubes. Center: the high pressure multi-anvil apparatus. Right: the monoclinic structure of the new phase: blue octahedra are SiO{sub 6} units and the yellow tetrahedra are PO{sub 4} units. Highlights: Black-Right-Pointing-Pointer Silicon phosphate transforms into a new phase at high pressure and temperature. Black-Right-Pointing-Pointer The high pressure phase is 14.8% denser than the low-pressure phase. Black-Right-Pointing-Pointer The structure is based on a linkage of SiO{sub 6} polyhedra and P{sub 2}O{sub 7} dimers. Black-Right-Pointing-Pointer The way the two units are packed is reminiscent of the CsCl arrangement. Black-Right-Pointing-Pointer The new structure is monoclinic and is a unique structure.« less

Authors:
 [1]; ; ; ;  [1]
  1. Department of Chemistry, Arizona State University, Tempe, AZ 85287-1604 (United States)
Publication Date:
OSTI Identifier:
22012151
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: . 190; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBIDES; CESIUM CHLORIDES; DIMERS; LATTICE PARAMETERS; MONOCLINIC LATTICES; MONOCRYSTALS; PYROPHOSPHATES; SILICON PHOSPHATES; SPACE GROUPS; SYMMETRY; TOPOLOGY

Citation Formats

Leinenweber, Kurt, E-mail: kurtl@asu.edu, Stearns, Linda A., Nite, Jacob M., Nemeth, Peter, and Groy, Thomas L. Structure of a new form of silicon phosphate (SiP{sub 2}O{sub 7}) synthesized at high pressures and temperatures. United States: N. p., 2012. Web. doi:10.1016/J.JSSC.2012.02.031.
Leinenweber, Kurt, E-mail: kurtl@asu.edu, Stearns, Linda A., Nite, Jacob M., Nemeth, Peter, & Groy, Thomas L. Structure of a new form of silicon phosphate (SiP{sub 2}O{sub 7}) synthesized at high pressures and temperatures. United States. doi:10.1016/J.JSSC.2012.02.031.
Leinenweber, Kurt, E-mail: kurtl@asu.edu, Stearns, Linda A., Nite, Jacob M., Nemeth, Peter, and Groy, Thomas L. Fri . "Structure of a new form of silicon phosphate (SiP{sub 2}O{sub 7}) synthesized at high pressures and temperatures". United States. doi:10.1016/J.JSSC.2012.02.031.
@article{osti_22012151,
title = {Structure of a new form of silicon phosphate (SiP{sub 2}O{sub 7}) synthesized at high pressures and temperatures},
author = {Leinenweber, Kurt, E-mail: kurtl@asu.edu and Stearns, Linda A. and Nite, Jacob M. and Nemeth, Peter and Groy, Thomas L.},
abstractNote = {A new high-pressure phase of SiP{sub 2}O{sub 7} has been found and its crystal structure solved and refined from a single crystal grown at a condition of 16 GPa and 2000 Degree-Sign C and recovered to ambient conditions. The material is monoclinic, with the space group P2{sub 1}/c and lattice parameters a=4.3042(7) A, b=7.1505(12) A, c=6.2897(11) A, {beta}=103.805(2). The structure contains SiO{sub 6} octahedra in a corner-sharing arrangement with P{sub 2}O{sub 7} dimers, the same structural elements and vertex-sharing present in all the low-pressure forms of SiP{sub 2}O{sub 7}. However, the network is more condensed: the topology of the packing of SiO{sub 6} octahedra and P{sub 2}O{sub 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{sub 2}O{sub 7}. The structural data indicates that the P{sub 2}O{sub 7} dimers are linear (P-O-P angle=180 Degree-Sign ), an unusual feature for phosphates. - Graphical abstract: Single crystals of a new form of SiP{sub 2}O{sub 7} were synthesized at high pressure and temperature and the structure solved. Left: the high pressure multi-anvil assembly in a nest of 25.4 mm carbide anvil cubes. Center: the high pressure multi-anvil apparatus. Right: the monoclinic structure of the new phase: blue octahedra are SiO{sub 6} units and the yellow tetrahedra are PO{sub 4} units. Highlights: Black-Right-Pointing-Pointer Silicon phosphate transforms into a new phase at high pressure and temperature. Black-Right-Pointing-Pointer The high pressure phase is 14.8% denser than the low-pressure phase. Black-Right-Pointing-Pointer The structure is based on a linkage of SiO{sub 6} polyhedra and P{sub 2}O{sub 7} dimers. Black-Right-Pointing-Pointer The way the two units are packed is reminiscent of the CsCl arrangement. Black-Right-Pointing-Pointer The new structure is monoclinic and is a unique structure.},
doi = {10.1016/J.JSSC.2012.02.031},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = . 190,
place = {United States},
year = {2012},
month = {6}
}