A Mixed Valent Molybdenum Monophosphate with a Bidimensional Connection of MoO6Octahedra:Li3Mo3O5(PO4)3

✍ Scribed by S. Ledain; A. Leclaire; M.M. Borel; J. Provost; B. Raveau

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 465 KB
• Volume: 133
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7482

✦ Synopsis

A new mixed-valent molybdenum monophosphate Li 3 Mo 3 O 5 (PO 4 ) 3 with an original structure has been isolated. It crystallizes in the space group P1 with a ‫؍‬ 11.964, b ‫؍‬ 12.716, c ‫؍‬ 8.274 A s , ‫؍‬ 90.26°, ‫؍‬ 96.87°, and ‫؍‬ 89.67°. It is to date the only mixed-valent molybdenum phosphate that exhibits layers of corner-sharing octahedra. The latter, with formulation [Mo 8 O 37 ] R , are built up of HTB (hexagonal tungsten bronze) rows of octahedra running along b. The 3D [Mo 3 P 3 O 17 ] R framework results from the stacking of [Mo 8 O 37 ] R layers with [MoPO 7 ] R layers along a, with two successive layers being connected through single PO 4 tetrahedra. Within this framework, the lithium cations exhibit two kinds of coordination, tetrahedral and pyramidal. Examination of the Mo-O distances and the bond valence calculations suggests an ordering of the Mo(V) and Mo(VI) species, but the magnetic susceptibility measurements show a partial electronic delocalization for T > 10 K, whereas an antiferromagnetic ordering is evidenced below 7 K.