A New High-Temperature Cubic Fluorite-Type Phase Mo0.16Bi0.84O1.74 with a Rare Three-Dimensional Incommensurate Modulation

✍ Scribed by M. Valldor; S. Esmaeilzadeh; C. Pay-Gomez; J. Grins

• Book ID: 102606767
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 163 KB
• Volume: 152
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8742

✦ Synopsis

A new high-temperature phase Mo 0.16 Bi 0.84 O 1.74 was obtained by quenching from 8003C. Its average structure is of the cubic Fm3 m 6ourite type with a ‫؍‬ 5.6478(1) A > and was re5ned from single-crystal Mo K X-ray di4raction (XRD) data to a weighted R-value of 3.7% for 16 unique re6ections and isotropic thermal displacement parameters re5ned for the metal atoms, U iso ‫؍‬ 0.0564(4) A > 2 , and the O atoms, U iso ‫)6(681.0؍‬ A > 2 . The structure exhibits in addition a novel 3-D incommensurate modulation that was studied by electron di4raction and both powder and single crystal XRD. Extinction conditions indicate the symmetry P:Fm3 m:Fm3 m, which has previously only been reported once. The three q-vectors are along the unit cell axes and have lengths of 0.29256(6) unit cells in reciprocal space. The modulated structure is compared with the previously reported and similarly modulated structure of the solid solution Nb x Bi 1؊x O 1.5؉x , with 0.124x40.46 and symmetry P:Fm3 m: Fd3 m.