Synthesis and Investigation of Tin(II) Pyrophosphate Sn₂P₂O₇.

Abstract

Structure D 2000Synthesis and Investigation of Tin(II) Pyrophosphate Sn 2 P 2 O 7 . -The title compound is prepared by heating a stoichiometric mixture of SnO and NH4H2PO4 at 820 K for 24 h and characterized by single crystal and powder XRD, and 119 Sn Moessbauer spectroscopy. The low-temperature β-modification crystallizes in the triclinic space group P1 with Z = 4. The structure contains [P2O7] 4groups oriented in mutually perpendicular directions with Sn atoms situated in large structural interstices. The title compound undergoes a structural transition at 623 K. The high-temperature α-form crystallizes in the monoclinic space group P21/n with Z = 2. -(CHERNAYA, V. V.; MITIAEV, A. S.; CHIZHOV, P. S.; DIKAREV, E. V.; SHPANCHENKO*, R. V.; ANTIPOV, E. V.; KOROLENKO, M. V.; FABRITCHNYI, P. B.; Chem. Mater. 17 (2005) 2, 284-290; Dep. Chem., Moscow State Univ., Moscow 119889, Russia; Eng.) -W. Pewestorf

Network Structure and Connectivity in SnO–P2O5 Glasses: Results from 2D 31P and 119Sn NMR Spectroscopy

“…1−4 Interest in tin phosphate (SnO−P 2 O 5 ) glasses is driven primarily by their high refractive index, zero stress-optic response, and low glass transition temperature T g , making them suitable for applications in optics as well as in low-temperature glass-to-metal sealing. 5−9 The structure of tin phosphate glasses has been investigated extensively in recent years using a variety of characterization techniques including infrared and Raman spectroscopy as well as 31 P and 119 Sn NMR spectroscopy. 9 31 P magic-angle-spinning (MAS) NMR spectroscopic measurements played a key role in the identification and quantitation of the various PO 4 Q n species in phosphate glasses, where n represents the number of bridging oxygen (BO) atoms in each PO 4 tetrahedron.…”

“…9 31 P magic-angle-spinning (MAS) NMR spectroscopic measurements played a key role in the identification and quantitation of the various PO 4 Q n species in phosphate glasses, where n represents the number of bridging oxygen (BO) atoms in each PO 4 tetrahedron. However, unlike alkali, alkaline-earth, Zn-, or Pb-phosphate glasses, the 31 P MAS NMR spectra of the tin phosphate glasses display strongly overlapping resonances corresponding to various Q species, making an unequivocal quantitation of the latter via simulation of the spectral line shapes a challenging task. Additional structural information including the phosphorus site symmetry and conformation for the PO 4 tetrahedra in various Q n species can only be gained from the determination of the full 31 P chemical shift tensor.…”

“…However, unlike alkali, alkaline-earth, Zn-, or Pb-phosphate glasses, the 31 P MAS NMR spectra of the tin phosphate glasses display strongly overlapping resonances corresponding to various Q species, making an unequivocal quantitation of the latter via simulation of the spectral line shapes a challenging task. Additional structural information including the phosphorus site symmetry and conformation for the PO 4 tetrahedra in various Q n species can only be gained from the determination of the full 31 P chemical shift tensor. 10 On the other hand, 119 Sn NMR spectroscopy was also used in previous studies to obtain the local environment of Sn in tin phosphate glasses.…”

“…In contrast, the two-dimensional (2D) isotropic−anisotropic correlation NMR experiments, such as magic-angle turning (MAT) 12 and phaseadjusted spinning sidebands (PASS), 13 can separate the isotropic and anisotropic chemical shift information in two dimensions and allow for the determination of their correlation in a single experiment. Here, we report the results of 2D 31 P and 119 Sn isotropic−anisotropic correlation NMR spectroscopic studies of the structure of (SnO) x (P 2 O 5 ) 100−x glasses with 35 ≤ x ≤ 55. These results are analyzed to build a model of the compositional evolution of the structure of these glasses.…”

“…14 Each 2D PASS spectrum was obtained using 16 t 1 points with 12 transients per point, and a recycle delay of 600 s. All the 31 P spectra were externally referenced to 85% H 3 PO 4 with δ iso at 0 ppm. The spectral line shapes of 31 P MAS and PASS NMR experiments were analyzed using the software DMFit. 15 2.3.…”