Affordable Access

Publisher Website

Modulated crystal structure of K4(NbO)2[Si8O21]

Authors
Journal
Journal of Alloys and Compounds
0925-8388
Publisher
Elsevier
Publication Date
Volume
209
Identifiers
DOI: 10.1016/0925-8388(94)91089-8
Disciplines
  • Earth Science
  • Geography

Abstract

Abstract K 4(NbO) 2[Si 8O 21] was synthesized in the hydrothermal system K 2O-Nb 2O 5-SiO 2-H 2O (T = 450–500°C; P = 1000–1200 bar; Cu capsule; KOH concentration, 5%–10%; 0.5 < Nb 2O 5: SiO 2 < 1). The triclinic structure was established from X-ray single-crystal diffraction: space group, P 1 ; a = 33.92(2) A ̊ , b = 10.950(6) A ̊ , c = 7.737(4) A ̊ ; α = 76.42(4)°, β = 72.10(5)°, γ = 89.81(5)°; V = 2650.8 A ̊ 3; D x = 2.927 g cm −3; Z = 5; R aniso = 0.042 for 8855 reflections. The new phase is isotypic with Cs 4(NbO 2[Si 8O 21]; however, it is characterized by one-dimensional commensurable structure modulation along the a axis: 0.2 a of K,Nb silicate is approximately the a axis of Cs,Nb silicate. The modulation is related to the changes in tilt angle between two parts of the “loop-branched dreier double chains” of SiO 4 tetrahedra, and to the shifts of K atoms.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments

More articles like this

Crystal structure of K2V8O21and Tl2V8O21

on Solid State Sciences Jan 01, 2005

Surfactant-free hydrothermal synthesis and charact...

on Ceramics International Jan 01, 2010

Effects of K4CuNb8O23on phase structure and electr...

on Physica B Condensed Matter Jul 01, 2012

Crystal structure in PrBa2Cu4O8single crystals

on Journal of Physics and Chemist... Jan 01, 2001
More articles like this..