Un nouvel ultraphosphate: CaYP7O20—préparation et structure cristalline

✍ Scribed by Aliou Hamady; Tahar Jouini

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 164 KB
• Volume: 111
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1252

✦ Synopsis

The general formula of the unambiguously characterized ultraphosphate anions is (\left[\mathrm{P}{(n+2)} \mathrm{O}{(3 n+5)}\right]^{n-}). Such anions are well known for (n=2,3,4), and 6 . The member corresponding to (n=5) with calcium and yttrium cations has been just prepared. Calcium yttrium ultraphosphate, (\mathrm{CaYP}{7} \mathrm{O}{20}), crystallizes in the monoclinic space group system (C 2 / c) with the following cell parameters: (a=) 24.666(11) (\AA, b=6.850(3) \AA, c=10.698(6) \AA, \beta=107.40(4)^{\circ}), (V=1725(1) \AA^{3}), and (Z=4). The structure has been solved by using 1074 independent reflections ((F>3 \sigma(F)) ) to final (R) and (R_{\mathrm{w}}) values of 0.041 and 0.039 , respectively. The (\left[\mathrm{P}{7} \mathrm{O}{20}\right]^{5-}) anion is an infinite ribbon containing centrosymmetrical 10 -member rings sharing three (\mathrm{PO}{4}) tetrahedra. Two of them are connected via three oxygen vertices to respectively three (\mathrm{PO}{4}) tetrahedra. The ((\mathrm{Ca}), Y) (\mathrm{O}{6}) octahedra are located in the tunnels running in the same direction as the anion ribbons; they share all their corners with (\mathrm{PO}{4}) tetrahedra. O 1994 Academic Press, Inc.