Ag1.2V3O8Crystal Structure: Relationship with Ag2V4O11−yand Interpretation of Physical Properties

Abstract It is demonstrated that the Ag1+xV3O8phase can derive from a sprouting phenomenon easily occurring in the Ag2V4O11vanadate. The oxygen departure rough formula Ag2V4O11−ydrives to the formation of the title phase fory=0.16. Single crystals were obtained and fully characterized by X-ray single-crystal techniques. Ag1.2V3O8crystallizes in the monoclinic system, space groupP21/m,a=7.382(5) A,b=3.6029(6) A,c=12.193(8) A,β=107.39(6)°,Z=2, and is isostructural with Li1+xV3O8. Structural relationships with Ag2V4O11−yare detailed. It is shown that silver atoms, located between the [V3O8]nlayers formed by association of two octahedra and a trigonal bipyramid by edge and corner sharing, occupy two crystallographic sites. Electron density computations show that silver atoms move along the [010] direction, explaining the interesting electrochemical properties. Magnetic measurements establish the perfect correspondence between inserted Ag+ions and the V4+yield, giving the formula Ag1+yV5+3−yV4+yO8.