ChemInform Abstract: Refinement of the CsYP2O7 Crystal Structure by the Rietveld Method.

Abstract

structure structure (solids and liquids) D 2000 -001Refinement of the CsYP2O7 Crystal Structure by the Rietveld Method.-The structure of the title compound, characterized by the powder XRD data, is refined by the Rietveld method. CsYP2O7, prepared from a stoichiometric mixture of Cs2CO3, Y2O3 and (NH4)2HPO4 at 740 • C, crystallizes in the monoclinic space group P21/c with Z = 4. The structure which is isotypic with M(I)M(III)P2O7 (M(I): K, Rb, Cs; M( III): Fe, V, Mo, Ti) consists of layers of M(III)P2O11 units, composed of diphosphate groups linked to M(III)O6 octahedra, forming a three-dimensional framework. The large size of the Cs+ and Y3+ cations has a significant influence on the distortions of the CsO10 and P2O7 polyhedra and thus explains the lower thermal stability of CsYP2O7 as compared to RbYP2O7. -(AKRIM, A.; ZAMBON, D.; METIN, J.; COUSSEINS, J.-C.; C. R.

Two potassium rare-earth polyphosphates KLn(PO3)4 (Ln=Ce, Eu): Structural, optical, and electronic properties

“…So, a decreased concentration fluorescence quenching may Table 3 Selected bond distances (Å) and angles (1) Symmetry codes: (i) Àx, À0.5+y, 2Àz; (ii) 1Àx, À0.5+y, 2Àz; (iii) Àx, À0.5+y, 1Àz; (iv) 1Àx, 0.5+y, 1Àz; (v) À1+x, y, z; (vi) 1Àx, À0.5+y, 1Àz; (vii) 1+x, y, z; (viii) x, À1+y, z; (ix) x, 1+y, z; (x) 1Àx, 0.5+y, 2Àz; (xi) Àx, 0.5+y, 2Àz; (xii) Àx, 0.5+y, 1Àz. be predicted [19,20]. When the coordination of the K atom for 1 is compared with that for the polymorph with space group P2 1 /n [11], it can be noted that the coordination numbers of the K atom in the two polymorphs are different.…”

Luminescence – structure relationships in MYP2O7:Eu3+ (M=K, Rb, Cs)

“…As mentioned above, the MYP 2 O 7 (M¼K, Rb, Cs) pyrophosphates are isostructural and crystallize in the monoclinic system [2,16,17]. The crystal structure of CsYP 2 O 7 is depicted in Fig.…”

Structural, Luminescence, and Electronic Properties of Potassium Holmium Cyclotetraphosphate KHoP4O12: Experiment and Theory

“…So, a decreased concentration fluorescence quenching may be predicted. [23,24] The potassium atom located in the tunnels of the 3D framework is ten-coordinated with the K-O bond lengths of 2.738(3)-3.379(3) Å (Table 3), four oxygen atoms of which are shared by neighboring HoO 8 polyhedra. However, it is noted that the oxygen coordination number of the lithium atom for LiHo(PO 3 ) 4 [13] is only four, resulting in the difference of the crystal structures for KHoP 4 O 12 and LiHo(PO 3 ) 4 .…”