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HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHS VOLUME 41 HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHS Advisory Editorial Board G.-y. ADACHI, Kobe, Japan W.J. EVANS, Irvine, USA S.M. KAUZLARICH, Davis, USA G.H. LANDER, Karlsruhe, Germany M.F. REID, Christchurch, New Zealand Editor Emeritus ✠ LeRoy EYRING , Tempe, USA ✠ Deceased. HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHS VOLUME 41 EDITORS Karl A. GSCHNEIDNER, Jr. Member, National Academy of Engineering The Ames Laboratory, U.S. Department of Energy, and Department of Materials Science and Engineering Iowa State University Ames, Iowa 50011-3020 USA Jean-Claude G. BU¨ NZLI Swiss Federal Institute of Technology, Lausanne (EPFL) Laboratory of Lanthanide Supramolecular Chemistry BCH 1402 CH-1015 Lausanne Switzerland Vitalij K. PECHARSKY The Ames Laboratory, U.S. Department of Energy, and Department of Materials Science and Engineering Iowa State University Ames, Iowa 50011-3020 USA Amsterdam Boston Heidelberg London New York Oxford Paris San Diego San Francisco Singapore Sydney Tokyo North-Holland is an imprint of Elsevier North-Holland is an imprint of Elsevier Radarweg 29, POBox 211, 1000AEAmsterdam, TheNetherlands The Boulevard, Langford Lane, Kidlington, OxfordOX5 1GB,UK Copyright# 2011 Elsevier B.V. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher. Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: PREFACE Karl A. Gschneidner Jr., Jean-Claude G. Bu¨nzli, Vitalij K. Pecharsky These elements perplex us in our reaches [sic], baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us— mocking, mystifying, and murmuring strange revelations and possibilities. Sir William Crookes (February 16, 1887) Volume 41 of the Handbook on the Physics and Chemistry of Rare Earths adds four chapters to the series: two focus on nanoscale rare-earth materials, while the other two are concerned with divergent topics—the arrangement of the rare-earth elements in the periodic table, and the higher order rare-earth chalogenide compounds with the elements of the 14th group and also In. The first chapter (248) discusses the various proposals suggested for the location of the rare-earth elements in the periodic table from the time of Mendeleev to the present day. The rare- earth containing buckyballs, that is, carbon fullerenes with encapsulated metal atom(s), which may exhibit a variety of behaviors—metals, semiconductors, and insulators—are described in Chapter 249. The ternary and quaternary rare-earth chalogenide compounds with the group 14 elements (Si, Ge, Sn and Pb) and In feature a wide range of stoichiome- tries, and both simple and complex crystal structures, and may have unusual applications (Chapter 250). The final chapter (251) describes the synthesis, chemical behaviors, and physical properties of inorganic compounds at the nanoscale. Each chapter concludes with a perspective of the future of the field. v vi Preface CHAPTER 248. ACCOMMODATION OF THE RARE EARTHS IN THE PERIODIC TABLE: A HISTORICAL ANALYSIS By PIETER THYSSEN AND KOEN BINNEMANS Katholieke Universiteit Leuven, Belgium Sc Sc Y Y OR ? La Lu Ac Lr This chapter gives an overview of the evolution of the position of the rare earths in the periodic table, from Mendeleev’s time to the present. Three fundamentally different accommodation methodologies have been proposed over the years. Mendeleev considered the rare-earth elements as homologs of the other elements. Other chemists looked upon the rare earths as forming a special intraperiodic group and they clustered the rare-earth elements in one of the groups of the periodic table. Still others adhered to the intergroup accommodation of the rare earths, according to which the rare-earth elements do not show any relationship with the other elements, so that they had to be placed within the periodic table as a separate family of elements. The intergroup accommodation became the preferred one in the twentieth century. The advantages and disadvantages of the different representations of the modern periodic table are discussed. Preface vii CHAPTER 249. METALLOFULLERENES By HISANORI SHINOHARA AND YAHACHI SAITO Nagoya University, Nagoya, Japan Endohedral metallofullerenes (fullerenes with metal atom(s) encapsulated) are novel forms of fullerene-based materials that have attracted wide interest during the past decades, not only in physics and chemistry but also in such interdisciplinary areas as material and biological sciences. In this article, advances in the production, separation (isolation), and various spectroscopic characterizations of endohedral metallofullerenes are presented in an attempt to clarify their structural, electronic, and solid-state properties. The endohedral metallofullerenes produced so far are centered on group 2 and 3 metallofullerenes, such as Sr and Ba, and Sc, Y, and La as well as lanthanide metallofullerenes (Ce–Lu). These metal atoms have been encapsulated in higher fullerenes, 13 especially in C82. Synchrotron X-ray diffraction and C NMR and ultra- high vacuum scanning tunneling microscopy (UHV-STM) studies have revealed that metal atoms are indeed encapsulated by the carbon cage and that the metal atoms are not in the center of the fullerene cage but sit close to the carbon cage, indicating the presence of a strong metal–cage interaction. Electron spin resonance and theoretical calculations reveal that substantial electron transfer takes place from the encaged metal atom to the carbon cage: intrafullerene electron transfers. One of the most distinct features of such a metallofullerene is superatom character, by which the metallofullerene can be viewed as a positively charged core metal surrounded by a negatively charged carbon cage. Structural and viii Preface electronic analyses based on X-ray diffraction and UHV-STM measure- ments indeed provide evidence of such character. Endohedral metallofullerenes can be metals, small-gap semiconductors, or insulators, depending upon the fullerene size and the kind and the number of metal atoms encapsulated. Finally, some prospective applications of metallofullerenes are presented. CHAPTER 250. TERNARY AND QUATERNARY CHALCOGENIDES OF Si, Ge, Sn, Pb, and In By LUBOMIR D. GULAY Volyn National University, Lutsk, Ukraine and MAREK DASZKIEWICZ W. Trzebiatowski Institute of Low Temperature and Structure Research, Wrocław, Poland YbLaS3 ErCuPbS3 ErCuPbSe3 SG Cmcm SG Cmcm SG Pnma a = 0.39238 nm a = 0.3916 nm a = 1.04846 nm b = 1.2632 nm b = 1.2934 nm b = 0.40424 nm c = 0.9514 nm c = 1.0106 nm c = 1.34143 nm Pb La Pb Er Yb Er Cu Cu c c a b b c a a b Complex ternary, quaternary, and multicomponent chalcogenides containing rare earths are interesting because of potential applications in the fields of ionic conductivity and nonlinear optics. Gulay and Daszkiewicz review the current knowledge about experimental investigation of phase diagrams, crystallography, crystallographic relationships among known ternary and quaternary rare-earth chalcogenides, and the general principles governing the formation of rare-earth chalcogenides with Si, Ge, Sn, Pb, and In. The information presented in this chapter may serve as a guideline for preparation of small quantities of these novel materials for studies of their basic physical properties, and for those interested in preparing large quantities ofmaterials in order to explore their potential for practical applications. Preface ix CHAPTER 251. CONTROLLED SYNTHESIS AND PROPERTIES OF NANOMATERIALS By CHUN-HUA YAN, ZHENG-GUANG YAN, YA-PING DU, JIE SHEN, CHAO ZHANG, AND WEI FENG Peking University, Beijing, China A 3030 B SP 1120 50 nm 50 nm Rare-earth nanomaterials find numerous applications as phosphors, catalysts, permanent magnets, fuel cell electrodes and electrolytes, hard alloys, and superconductors. Yan and coauthors focus on inorganic non- metallic rare-earth nanomaterials prepared using chemical synthesis routes, more specifically, prepared via various solution-based routes. Recent discoveries in synthesis and characterization of properties of rare-earth nanomaterials are systematically reviewed. The authors begin with ceria and other rare-earth oxides, and then move to oxysalts, halides, sulfides, and oxysulfides. In addition to comprehensive description of synthesis routes that lead to a variety of nanoforms of these interesting materials, the authors pay special attention to summarizing most impor- tant properties and their relationships to peculiar structural features of nanomaterials synthesized over the last 10–15 years.