Crystal structure of Cd₂P₂O₇

Abstract

Cadmium pyrophosphate forms crystals having triclinic synlnletry with the unit cell parameters a = 6.672(8) A, b = 6.623(8) A, c = 6.858(7) A, a = 95.80(10)", P = 115.38(8)", and y = 82.38(8)".The space group is Pi and there are two n~olecules per unit cell. The structure was refined by least squares methods using 1326 reflections. The pyrophosphate anion, Pz07"-, has a bent P-0-P bond with a bond anele of 132" and with average inner and outer PO bond lengths of 1.62 and 1.51 A. resoectivelv.The cations are coordinated to five and six oxygen atoms with aierage cadmium-oxygen atbm bond lengths of 2.33 and 2.31 A, respectively. This pyrophosphate structure differs from that adopted by other divalent metal ions of small radius in that the ends of the anion are in a nearly eclipsed orientation but shows some similarity to those AZBZO7 compounds, where A has a large radius and B a small one.

Crystal Structure Refinement and Magnetic Properties of Fe4(P2O7)3 Studied by Neutron Diffraction and Mössbauer Techniques

“…Despite many tests, we did not manage to correct these anomalies. However, it should be noted that similar short P}O distances were also observed in some phosphates and diphosphates (1.43 A > ) (15,16 (4)] iron planes. These layers are alternatively stacked along the screw axis through (P O )\ units ( Fig.…”

Molecular-distortion analysis with Cartesian symmetry coordinates

“…dron Li06 maintains only the inversion center, and finally Mn06 conserves a symmetry plane, parallel to (010). Cd2P207 (Calvo & Au, 1969) belongs to the triclinic system, space group P1, with two molecular units in the unit cell. The two tetrahedral clusters, which form the pyrophosphate unit, and the CdO6 octahedron are so strongly distorted that they do not have any symmetry element, and belong to the trivial symmetry group, C1.…”

Calcium Phosphates in Biological and Industrial Systems

“…Alternatively, if the interaction of the metal ion with calcium phosphate is not known, it may be deduced by the combination of the analysis for the metal present in the solution and by the amount of titrant solutions added in order to keep the concentration constant. 42,49,109 From the rates of titrants added for constant supersaturation maintenance both in the absence and in the presence of metal ions, it is possible to obtain accurate values for the rates of crystallization. By the adjustment of the concentration of the titrant solutions it is possible to measure accurately even very low rates of crystallization, unattainable by other methods.…”