Données cristallographiques du phosphate acide de potassium d'anion mixte ortho- et pyro- K2H8 (PO4)2 P2O7

Norbert, Alain; Maurin, M.; André, Danielle; Larbot, A.

doi:10.3406/bulmi.1970.6517

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“…The presence of both phosphate and diphosphate groups in the same compound is infrequent. Nevertheless, it has been observed in some compounds, e.g., Na 6 [ThPO 4 (P 2 O 7 )] 2 , Na 7 M III 4 PO 4 (P 2 O 7 ) 4 (M III = Al, Cr, Fe), K 2 H 8 (PO 4 ) 2 P 2 O 7 , Rb 3 Ti 3 O(PO 4 ) 3 P 2 O 7 , ξ-Ag(MoO) 2 PO 4 P 2 O 7 , Ca 8 (PO 4 ) 4 (P 2 O 7 ), and Ca 2 VPO 4 P 2 O 7 …”

Section: Discussionmentioning

confidence: 99%

Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

et al. 1996

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The chemistry of thorium phosphate reported in the literature has been found to be erroneous. It was reconsidered in terms of careful chemical preparations and specific analytical methods. Special attention has been paid to the atom ratio value referred to r = thorium/phosphorus, which was experimentally fixed in order to obtain the correct composition of the final compound. A new compound with the chemical formula Th4(PO4)4P2O7, derived from the crystal structure determination, has been obtained. The unit cell parameters were obtained from powder and single-crystal X-ray diffraction data. It is orthorhombic (space group Pcam, Z = 2) with the cell dimensions a = 12.8646(9) Å, b = 10.4374(8) Å, c = 7.0676(5) Å, and V = 949.00(9) Å3. The atomic positions were derived from Patterson and Fourier methods and the structure was refined to an R value of 0.039. The structure consists of layers parallel to (010) containing both PO4 and P2O7 groups. These layers alternate with planes of Th atoms. The coordination sphere of the two independent heavy atoms is formed by eight O atoms from five PO4 and one P2O7 groups. The formula of thorium phosphate Th4(PO4)4P2O7 is in good agreement with the elementary composition derived from electron microprobe analysis, which gave a ratio r = 2/3. Any other value of r (1/2 < r < 3/4) induces the formation of polyphase systems: Th4P6O23 and ThO2 for r > 2/3; Th4P6O23 and ThP2O7 for r < 2/3. The characterization of thorium phosphate diphosphate by means of infrared spectroscopy confirmed the presence of diphosphate groups in the compound.

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Section: Discussionmentioning

confidence: 99%

Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

et al. 1996

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Sur L'Existence d'un Intermediaire Reactionnel Entre Phosphate et Pyrophosphate Acide de Potassium: Cas de K₂H₈(PO₄)₂P₂O₇

Larbot

Norbert

Durand

1982

Zeitschrift anorg allge chemie

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On the Existence of Intermediate Reaction Products of Potassium Hydrogen Phosphate and Diphosphate: K2H8(PO4)2P2O7 The crystal structure of K2H8(PO4)2P2O7 has been determined from diffractometer data obtained using MoKα radiation. The space group is Pca21 with a = 9.364(2), b = 7.458(2) and c = 19.560(2) Å, V = 1 366.0 Å3; dm = 2.17(1) g/cm3. Z = 4 · μ(MoKα) = 12.47 cm−1. The structure was solved by direct methods. The crystal structure was refined to R = 0.025 for 416 independent reflexions. Two kinds of PO4 exist and the mean value of PO is 1.55(2) Å for one and 1.53(2) Å for the other. In P2O7 the angle POP is 135(1)°. The distances PO of bridge are 1.59(2) and 1.57(2) Å the mean value of PO in terminals PO3 is 1.51(2) Å. The coordination numbers of the potassium ions are nine and eight. K2H8(PO4)2P2O7, compound with mixed anion PO4/P2O7 may be considered as reactional intermediary between acid orthophosphate and pyrophosphate.

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Données cristallographiques du phosphate acide de potassium d'anion mixte ortho- et pyro- K2H8 (PO4)2 P2O7

Cited by 2 publications

References 0 publications

Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Sur L'Existence d'un Intermediaire Reactionnel Entre Phosphate et Pyrophosphate Acide de Potassium: Cas de K₂H₈(PO₄)₂P₂O₇

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Données cristallographiques du phosphate acide de potassium d'anion mixte ortho- et pyro- K2H8 (PO4)2 P2O7

Cited by 2 publications

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Th4(PO4)4P2O7, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Th4(PO4)4P2O7, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Sur L'Existence d'un Intermediaire Reactionnel Entre Phosphate et Pyrophosphate Acide de Potassium: Cas de K2H8(PO4)2P2O7

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Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Th₄(PO₄)₄P₂O₇, a New Thorium Phosphate: Synthesis, Characterization, and Structure Determination

Sur L'Existence d'un Intermediaire Reactionnel Entre Phosphate et Pyrophosphate Acide de Potassium: Cas de K₂H₈(PO₄)₂P₂O₇