Infinitely Adaptive Transition-Metal Ordering in Ln2O2MSe2-Type Oxychalcogenides.
A number of Ln2O2MSe2 (Ln = La and Ce; M = Fe, Zn, Mn, and Cd) compounds, built from alternating layers of fluorite-like [Ln2O2](2+) sheets and antifluorite-like [MSe2](2-) sheets, have recently been reported in the literatures. The available MSe4/2 tetrahedral sites are half-occupied, and different compositions display different ordering patterns: [MSe2](2-) layers contain MSe4/2 tetrahedra that are exclusively edge-sharing (stripe-like), exclusively corner-sharing (checkerboard-like), or mixtures of both. This paper reports 60 new compositions in this family. We reveal that the transition-metal arrangement can be systematically controlled by either Ln or M doping, leading to an "infinitely adaptive" structural family. We show how this is achieved in La2O2Fe1-xZnxSe2, La2O2Zn1-xMnxSe2, La2O2Mn1-xCdxSe2, Ce2O2Fe1-xZnxSe2, Ce2O2Zn1-xMnxSe2, Ce2O2Mn1-xCdxSe2, La2-yCeyO2FeSe2, La2-yCeyO2ZnSe2, La2-yCeyO2MnSe2, and La2-yCeyO2CdSe2 solid solutions.
†Department of Chemistry, University Science Site, Durham University, South Road, Durham DH1 3LE, U.K.
Chris M
CM
Ainsworth
†Department of Chemistry, University Science Site, Durham University, South Road, Durham DH1 3LE, U.K.
Chun-Hai
CH
Wang
†Department of Chemistry, University Science Site, Durham University, South Road, Durham DH1 3LE, U.K.
Hannah E
HE
Johnston
†Department of Chemistry, University Science Site, Durham University, South Road, Durham DH1 3LE, U.K.
Emma E
EE
McCabe
‡ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory Didcot, Harwell, Oxford OX11 0QX, U.K.
Matthew G
MG
Tucker
§Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
Helen E A
HE
Brand
†Department of Chemistry, University Science Site, Durham University, South Road, Durham DH1 3LE, U.K.|¶Australian Nuclear Science and Technology Organisation, New Illawarra Road, Rutherford Avenue, Lucas Heights, New South Wales 2234, Australia.
John S O
JS
Evans