Etude Des Propriétés Physico-Chimiques De ZnRb 4 (P 3 O 9 ) 2 ·6H 2 O

The dehydration of ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O was investigated, between 25 and 600°;C, by TG-DTA, X-ray diffraction, IR. It leads, between 300 and 500°;C, to a mixture of long chain polyphosphates RbPO 3 and ZnRb 2 (PO 3 ) 4 which stays stable until its melting point. The IR (1400-30 cm m 1 ) and Raman spectra (1400-100 cm m 1 ) of ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O are reported and assignments of fundamental modes proposed and compared with theoretical results obtained via the MNDO method for P 3 O 9 ring with C s symmetry. (La déshydratation, sous pression atmosphérique, du cyclotriphosphate ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O, a ét´;e effectuée, entre 25 and 600°;C, par spectrométrie IR, diffraction des rayons X, ATG et ATD. Elle conduit, entre 300 and 500°;C, au mélange de polyphosphates RbPO 3 et ZnRb 2 (PO 3 ) 4 qui reste stable jusqu'à la fusion. Les spectres vibrationnels IR (1400-30 cm m 1 ) et Raman (1400-100 cm m 1 ) du sel étudié ont été interprétés dans le domaine des vibrations de valence et de déformation du cycle P 3 O 9 et comparés avec les résultats des calculs théoriques par la méthode MNDO pour un cycle isolé de symétrie C s .)     

Préparation Chimique,Caracterisation Cristallographique,Etudes Thermique et Vibrationnelle du Cyclotriphosphate Hexahydraté de Manganèse et de Tetra-Argent,MnAg 4 (P 3 O 9 ) 2 .6H 2 O

The cyclotriphosphate hexahydrate of manganese and silver, MnAg 4 (P 3 O 9 ) 2 .6H 2 O, was prepared by Boullé's process. MnAg 4 (P 3 O 9 ) 2 .6H 2 O crystallizes in the triclinic system, P-1, Z = 1 and its structure was determined by Rietveld's method. The refinement of 54 parameters by this method, using 1752 independent reflections leads to Rw p = 0.098, R p = 0.065 and R B = 0.033 on the basis of its isotype NiAg 4 (P 3 O 9 ) 2 .6H 2 O. The unit cell parameters of this salt are the following a = 8.824(1)Å, b = 8.485(1)Å, c = 6.609(1)Å, f = 90.30(1)°;, g = 92.89(1)°; and n = 107.28(1)°;. The thermal behavior of this new compound was studied, between 25 and 600°;C, under atmospheric pressure by infrared spectrometry, X-ray diffraction, thermal analyses TGA and DTA coupled. This study allows us the identification and the crystallographic characterization of a new phase, MnAg 2 (PO 3 ) 4 isotype of ZnRb 2 (PO 3 ) 4 , obtained between 350 and 450°;C, mixed with the long-chain polyphosphate of silver AgPO 3 . The kinetic characteristics of the dehydration of MnAg 4 (P 3 O 9 ) 2 .6H 2 O and the thermal phenomena accompanying this dehydration were determined and discussed on the basis of the proposed crystalline structure. The vibrational spectrum of the, MnAg 4 (P 3 O 9 ) 2 .6H 2 O, was examined and interpreted in the domain of the stretching vibrations of the P 3 O 9 rings, on the basis of the proposed crystalline structure and in the light of the calculation of the thirty fundamental IR frequencies for the idealized D 3h symmetry.     

Etude Des Proprietes Physico-Chimiques du Cyclotriphosphate Mixte de Nickel et D'argent Hexahydrate,NiAg 4 (P 3 O 9 ) 2 ·6H 2 O

We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate hexahydrate of nickel and silver, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, between 25 and 600°;C by infrared spectrometry, x-ray diffraction, thermal analyses TGA, and DTA. This study led us to the identification and the crystallographic characterization of a new phase, NiAg 4 (PO 3 ) 6 , obtained between 250 and 350°;C. NiAg 4 (PO 3 ) 6 crystallizes in the triclinic system, P m 1 , with the following unit cell parameters a = 6.100(2)Å, b = 6.783(1)Å, c = 10.764(2)Å, f = 78.66(3)°;, g = 96.85(3)°;, n = 113.36(2)°;, Z = 1, V = 401Å 3 , M(20) = 133, and F(30) = 88 (0.0017; 197). The calcination of NiAg 4 (PO 3 ) 6 , between 400 and 500°;C, leads to a mixture of long-chain polyphosphates NiAg(PO 3 ) 3 and AgPO 3 . The kinetic characteristics of the dehydration of NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O were determined and discussed. The vibrational spectrum of the title compound, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, was interpreted in the domain of the stretching vibrations of the P 3 O 9 rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P 3 O 9 ring with the idealized D 3h symmetry. L'étude de la déshydratation et de la calcination, sous pression atmosphérique, du cyclotriphosphate de nickel tétra-argent, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, a été effectuée, entre 25 et 600°;C, par spectrométrie IR, diffraction des rayons x, ATG, et ATD. Elle a permis l'identification et la caractérisation cristallographique d'une nouvelle phase, NiAg 4 (PO 3 ) 6 , obtenue entre 250 et 350°;C. NiAg 4 (PO 3 ) 6 cristallise dans le système triclinique, de groupe d'espace P m 1 avec Z = 1. Les paramètres de maille sont: a = 6.100(2)Å, b = 6.783(1)Å, c = 10.764(2)Å, f = 78.66(3)°;, g = 96.85(3)°;, n = 113.36(2)°;, V = 401Å 3 et les facteurs de mérite sont: M(20) = 133, et F(30) = 88 (0.0017; 197). La calcination du composé, entre 400 et 500°;C, conduit au mélange de polyphosphates à chaînes infinies NiAg(PO 3 ) 3 et AgPO 3 . Les caractéristiques cinétiques de la déshydratation de NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O ont été déterminées et discutées. Le spectre IR du sel étudié a été interprété, dans le domaine des vibrations de valence des cycles, sur la base de la structure cristalline connue de son isotype NiNa 4 (P 3 O 9 ) 2 ·;6H 2 O et de nos résultats de calcul des fréquences IR fondamentales du cycle P 3 O 9 3 m de symétrie idéale D 3h .     

Decomposition thermique et etude vibrationnelle de NiNa4(P3O9)2·6H2O

We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate tetrahydrate of nickel and sodium, NiNa₄(P₃O₉)₂·6H₂O, between 25 and 700°C by thermal analyses (TG, DTA) infrared spectrometry and X-ray diffraction. This study allows us the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)6, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P_–1, with the following unit cell parameters a=6.157(3) Å, b=6.820(6) Å, c=10.918(6) Å, =80.21(5)°, =97.80(9)°, =113.49(3)°, V=409.8 ų, Z=1, M(19)=25 and F(19)=48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂·6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)2·6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.

This revised version was published online in November 2005 with corrections to the Cover Date.