Crystal structures of two allotropic forms of Na2CoP2O7

The blue allotropic form of Co2+:Na2CoP2O7: optical and magnetic properties, correlation with crystallographic data

“…Erragh et al [4] The structure is characterized by layers of mixed tetrahedra of CoO 4 and P(PO 4 ) (thus ½CoP 2 O 7 À2 layers) alternating with layers of sodium atoms.…”

“…Among them the Na 2 CoP 2 O 7 compound has been particularly studied. Two new allotropic forms of this diphosphate have been characterized [4]: the first one is rose and belongs to the triclinic crystallographic system with a site symmetry C 1 for Co 2+ , the second one is blue and orthorhombic with a site symmetry C S for Co 2+ . A recent work [5], performed by some of us, specified the characteristics of the so-called orthorhombic blue form.…”

Luminescent Properties of Silver(I) Diphosphate of Compositions Na2−xAgxZnP2O7

“…The covalent character of the anionic entities is emphasized in layer-like structures in which phosphate groups are located in two-dimensional sublattices. Such an atomic arrangement is typical of alkali diphosphates, e.g., KYP O (3), Na ZnP O (4), and Na CoP O (blue form) (5), in which more or less alkali ion can be possibly replaced by Ag>. In this context, the object of the present investigation is an analysis of the relationship between the structure and the luminescent properties of compounds of the general formula Na \V Ag V ZnP O (0(x41).…”

“…The experimental conditions of the data collection are given in Table 1. Final coordinates and selected atomic distances (5) and angles are listed in Tables 2 and 3. Figure 4 compares the experimental and calculated X-ray di!raction patterns.…”

A Mixed Nickel–Lithium Pyrophosphate, LiNi1.5P2O7

“…These compounds are rarely mentioned in the literature (Erragh, Boukhari, Elouadi & Holt, 1991;Spirlet, Rebizant & Liegeois-Duyckaerts, 1993).…”