Jump to ContentJump to Main Navigation
Symmetry Relationships between Crystal StructuresApplications of Crystallographic Group Theory in Crystal Chemistry$
Users without a subscription are not able to see the full content.

Ulrich Müller

Print publication date: 2013

Print ISBN-13: 9780199669950

Published to Oxford Scholarship Online: December 2013

DOI: 10.1093/acprof:oso/9780199669950.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 26 January 2021

Topotactic reactions

Topotactic reactions

(p.216) (p.217) 16 Topotactic reactions
Symmetry Relationships between Crystal Structures

Ulrich Müller

Oxford University Press

A topotactic reaction is a chemical solid-state reaction such that the orientations of the product crystals are determined by the orientation of the initial crystal. The same symmetry rules apply for the domains as for phase transitions. Crystals of C70 (P63/mcm) polymerize in the solid state; the space group of poly-C70 (Cmcm) is a subgroup of P63/mcm of index 3 and thus twins with three orientations are the result. Vernier compounds are halides of the lanthanoids with the general formula LnnX2n+1, e.g., Tm7Cl15. Their structures are hettotypes of the CaF2 type. When they crystallize from a melt having some intermediate composition, topotactic textures result consisting of, say, TmCl2 and Tm7Cl15. Their domains are intergrown such that the X-ray diffraction pattern is puzzling. However, with group-subgroup relations the puzzle can be solved.

Keywords:   topotactic reaction, solid-state reaction, vernier compounds

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .