Crystal Structure of Silicon Pyrophosphate (Form I) from Powder Diffraction Data

Poojary, Damodara M.; Borade, Ramesh B.; Campbell, Fred L.; Clearfield, Abraham

doi:10.1006/jssc.1994.1273

Cited by 59 publications

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“…[39] and AlOPCl 6 . [28] In the case of the hexagonal form of SiP 2 O 7 [40] and α-Ca(PO 3 ) 2 , a geometry optimization was carried out starting from the experimental one and allowing the positions of all atoms to relax using DFT calculations. H-relaxed structure was used only in the case of α-NTO.…”

Section: Methodsmentioning

confidence: 99%

New perspectives in the PAW/GIPAW approach: JP-O-Si coupling constants, antisymmetric parts of shift tensors and NQR predictions

et al. 2010

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In 2001, Pickard and Mauri implemented the gauge including projected augmented wave (GIPAW) protocol for first-principles calculations of NMR parameters using periodic boundary conditions (chemical shift anisotropy and electric field gradient tensors). In this paper, three potentially interesting perspectives in connection with PAW/GIPAW in solid-state NMR and pure nuclear quadrupole resonance (NQR) are presented: (i) the calculation of J coupling tensors in inorganic solids; (ii) the calculation of the antisymmetric part of chemical shift tensors and (iii) the prediction of (14)N and (35)Cl pure NQR resonances including dynamics. We believe that these topics should open new insights in the combination of GIPAW, NMR/NQR crystallography, temperature effects and dynamics. Points (i), (ii) and (iii) will be illustrated by selected examples: (i) chemical shift tensors and heteronuclear (2)J(P-O-Si) coupling constants in the case of silicophosphates and calcium phosphates [Si(5)O(PO(4))(6), SiP(2)O(7) polymorphs and α-Ca(PO(3))(2)]; (ii) antisymmetric chemical shift tensors in cyclopropene derivatives, C(3)X(4) (X = H, Cl, F) and (iii) (14)N and (35)Cl NQR predictions in the case of RDX (C(3)H(6)N(6)O(6)), β-HMX (C(4)H(8)N(8)O(8)), α-NTO (C(2)H(2)N(4)O(3)) and AlOPCl(6). RDX, β-HMX and α-NTO are explosive compounds.

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Section: Methodsmentioning

confidence: 99%

New perspectives in the PAW/GIPAW approach: JP-O-Si coupling constants, antisymmetric parts of shift tensors and NQR predictions

et al. 2010

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“…The areas of these two peaks are normalised to 500 and results are thus reported as the number of ''pyro'' counts out of 500. Density calculations were performed using the POWD-12++ (1997) software using the ICSD values from the XRD data as obtained by Poojary et al [10,11].…”

Section: Catalyst Characterizationmentioning

confidence: 99%

“…Traditionally this has been improved by the use of additives such as fuller's earth, which act as ''bonding agents'' or binders [7][8][9]. In previous studies the structure of the SPA catalyst was investigated in terms of the preparation method and characterization of the different silicon phosphate phases present www.elsevier.com/locate/apcata Applied Catalysis A: General 308 (2006) 204-209 [10,11], but the effect thereof on crushing strength and other catalyst properties have not been reported.…”

Section: Introductionmentioning

confidence: 99%

An improved solid phosphoric acid catalyst for alkene oligomerization in a Fischer–Tropsch refinery

Coetzee

Mashapa

Prinsloo

et al. 2006

Applied Catalysis A: General

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“…Furthermore there are a small number of silicon phosphates that have been obtained at ambient pressure and these contain polymeric network structures of SiO 6 octahedra and PO 4 tetrahedra (e.g. SiP 2 O 7 (form I), [7] Rb 2 SiP 4 O 13 , [8] (NH 4 ) 2 SiP 4 O 13 [9] ). Owing to its enhanced basicity Si rather than P prefers the octahedral coordination in these compounds.…”

mentioning

confidence: 99%

Ce16Si15O6N32—An Oxonitridosilicate with Silicon Octahedrally Coordinated by Nitrogen

Köllisch¹,

Schnick²

1999

Angew. Chem. Int. Ed.

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A rarity in solid-state chemistry is octahedrally coordinated silicon. Ce Si O N is the first nitridosilicate with this structural motif. Most oxosilicates containing octahedrally coordinated silicon are high-pressure phases. In contrast to that Ce Si O N has been synthesized under ambient pressure. An SiN octahedron that is surrounded by two parallel rings formed from six Si(O,N) tetrahedra is depicted.

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Crystal Structure of Silicon Pyrophosphate (Form I) from Powder Diffraction Data

Cited by 59 publications

References 0 publications

New perspectives in the PAW/GIPAW approach: JP-O-Si coupling constants, antisymmetric parts of shift tensors and NQR predictions

New perspectives in the PAW/GIPAW approach: JP-O-Si coupling constants, antisymmetric parts of shift tensors and NQR predictions

An improved solid phosphoric acid catalyst for alkene oligomerization in a Fischer–Tropsch refinery

Ce16Si15O6N32—An Oxonitridosilicate with Silicon Octahedrally Coordinated by Nitrogen

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