๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

Ab Initio Determination of Bi4.86La1.14O9 Monoclinic Structure from Powder Neutron Diffraction Data. Characterization of the Related Solid Solution

โœ Scribed by S. Obbade; M. Drache; P. Conflant; E. Suard

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
558 KB
Volume
162
Category
Article
ISSN
0022-4596

No coin nor oath required. For personal study only.

โœฆ Synopsis

This paper deals with the ab initio determination of -Bi 4.86 La 1.14 O 9 monoclinic structure from powder neutron data using the Rietveld method, and with physical properties characterization of a related solid solution. -Bi 4.86 La 1.14 O 9 , obtained from the annealing of a quenched rhombohedral hightemperature 1 sample, is monoclinic, P 2/c, a โ€ซุโ€ฌ 9.4956(3) A > , b โ€ซุโ€ฌ 3.9742(1) A > , c โ€ซุโ€ฌ 7.0425(2) A > , โ€ซุโ€ฌ 104.700(2)3; Z โ€ซุโ€ฌ 1. The structure re5nement converged to R F โ€ซุโ€ฌ 0.043 and R Bragg โ€ซุโ€ฌ 0.047. The structure is built from cationic slabs parallel to (100) faces of the monoclinic cell. Each cell corresponds to one slab containing a mixed Bi 0.86 La 1.14 cationic layer (Bi (1) ) sandwiched between two equivalent bismuth layers (Bi (2) ). The cohesion of the cations in the slabs results from the presence of the oxygen atoms distributed over three sites. Six O (1) and two O (2) atoms form a slightly distorted cubical polyhedron around the mixed cationic site (Bi (1) ). Bi (2) atoms are surrounded by seven oxygen atoms in a very distorted polyhedron. The important delocalization of Bi (2) lone pairs toward the interslab spaces leads to signi5cant bonds with the adjacent slabs and to the cohesion of the structure. -Bi 4.86 La 1.14 O 9 is the low symmetry variety of a particular sample of a wide solid solution domain that, formulated Bi 1ุŠx La x O 1.5 , has been investigated for 0.154x40.325. The formation of this phase from the irreversible transformation of quenched-1 on heating and the subsequent transitions P 2 P 1 have been evidenced by thermodi4ractometry, conductivity measurements versus temperature, dilatometry, and thermal analyses. Thermal expansion coe7cients (ุ‹10 5 ) are for a, c, and/or lattice volume for a quenched-1 , , 2 , or 1

๐Ÿ“œ SIMILAR VOLUMES

The ab initio crystal structure determin
The ab initio crystal structure determination of ฮฑ-malonic acid from neutron powder diffraction data
โœ R.G. Delaplane; W.I.F. David; R.M. Ibberson; C.C. Wilson ๐Ÿ“‚ Article ๐Ÿ“… 1993 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 338 KB

The crystal structure of the a phase of malonic acid has been determined ab initio from high-resolution neutron powder diffrao tion data at 373 K. Thestructure is orthorhombic: a-7.64800( 1) A, b=5.0211 I (I) A, c= 11.55803(2) A, V,=443.84\_A3 with four molecules in the unit cell and is character&d

Ab-Initio Determination of La2Mo4O15 Cry
Ab-Initio Determination of La2Mo4O15 Crystal Structure from X-rays and Neutron Powder Diffraction
โœ F. Dubois; F. Goutenoire; Y. Laligant; E. Suard; P. Lacorre ๐Ÿ“‚ Article ๐Ÿ“… 2001 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 583 KB

The structure of La 2 Mo 4 O 15 has been determined from both high resolution X-ray and neutron powder di4raction data. This molybdate crystallizes in a monoclinic space group P2 1 /n with cell parameters a โ€ซ)2( 7530.9ุโ€ฌ A > , b โ€ซุโ€ฌ 12.7737(2) A > , c โ€ซุโ€ฌ 10.6408(2) A > , โ€ซุโ€ฌ 90.2491(6)3. The struct

Ab initio structure determination of anh
Ab initio structure determination of anhydrous sodium alendronate from laboratory powder X-ray diffraction data
โœ Minakshi Asnani; K. Vyas; Apurba Bhattacharya; Surya Devarakonda; Santu Chakrabo ๐Ÿ“‚ Article ๐Ÿ“… 2009 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 292 KB

Sodium alendronate, a member of bisphosphonate class of compounds commonly used for treatment of generalized bone disorders, exists in various hydrated forms. Dehydration of sodium alendronate trihydrate has been studied using variable temperature X-ray powder diffraction technique. The crystal stru