Articles
All articles | Recent articles
Solid Solution in LnTiO2N and MTaO2N Oxynitrides, Ln = La,Nd; M = Ca, Sr, Ba
J. Ahchawarattaworn, D.P. Thompson
School of Chemical Engineering and Advanced Materials, University of Newcastle, Newcastle upon Tyne, NE1 7RU, U.K.
received February 12, 2014, received in revised form April 04, 2014, accepted May 09, 2014
Vol. 5, No. 3, Pages 173-183 DOI: 10.4416/JCST2014-00003
Abstract
The last fifty years have witnessed a considerable level of interest in the field of oxynitrides. This has mainly been because of their thermal and mechanical properties, but certain members of this group have the perovskite atomic arrangement, and as such might be expected to have interesting electrical and electronic properties. Foremost among these are the rare earth titanium oxynitrides, LnTiO2N, with Ln = La and Nd the two rare earths most commonly investigated, and also the Group II tantalum oxynitrides of the type MTaO2N where M = Ca, Sr and Ba. The present paper explores the changes in structure which occur in solid solutions between end-members of these two series. In the (LapNd1-p)O2N series, the Pnma space group of the Nd end-member is retained up to p = 0.8 in the above formula; in the (BapSr1-p)TaO2N series, the cubic structure of BaTaO2N is retained up to p ∼ 0.5 before transforming into the tetragonal modification of SrTaO2N; in the (CapSr1-p)TaO2N series, the tetragonal structure of SrTaO2N is stable up to p ∼ 0.65 before changing into the orthorhombic form of CaTaO2N. No evidence was found for solid solutions between CaTaO2N and BaTaO2N.
Download Full Article (PDF)
Keywords
Oxynitrides, perovskites, synthesis, crystal structure, dielectric properties
References
1 Thompson, D.P.: Oxynitride research in the nano era, Mater. Sci. Forum, 554, 1 – 10, (2007).
2 Marchand, R., Pors, F., Laurent, Y.: Preparation and characterization of new oxynitrides with a perovskite structure, (in French), Rev. Int. Hautes Tempér. Réfract. Fr., 23, 11 – 15, (1986).
3 Gouin, X., Marchand, R., Laurent, Y., Gervais, F.: Infrared dielectric response of BaTaO2N, Sol. State Comms., 93, 857 – 9, (1995).
4 Kim, Y.-I., Woodward, P.M., Baba-Kishi, K.Z., Tai, C.W.: Characterization of the structural, optical and dielectric properties of oxynitride perovskites AMO2N (A = Ba, Sr, Ca; M=Ta,Nb), Chem. Mater., 16, 1267 – 76, (2004).
5 Marchand, R., Laurent, Y., Guyader, J., L'Haridon, P., Verdier, P.: Nitrides and oxynitrides: preparation, crystal chemistry and properties, J. Eur. Ceram. Soc., 8, 197 – 213, (1991).
6 Clarke, S.J., Guinot, B.P., Michie, C.W., Calmont, M.J.C., Rosseinsky, M.J.: Oxynitride perovskites: synthesis and structures of LaZrO2N, NdTiO2N and LaTiO2N and comparison with oxide perovskites, Chem. Mater., 14, 288 – 94, (2002).
7 Pors, F., Bacher, P., Marchand, R., Laurent, Y., Roult, G.: Structural study of the oxynitride perovskite SrTaO2N and the solid solution Ba1-xSrxTaO2N by neutron diffusion, Rev. Int. Hautes Tempér. Réfract. Fr., 24, 239 – 46, (1988).
8 Günther, E., Hagenmayer, R., Jansen, M.: Structural studies of the oxynitrides SrTaO2N, CaTaO2N and LaTaON2 by means of neutron and X-ray diffraction, (in German), Z. Anorg. Allg. Chem., 626, 1519 – 25, (2000).
9 Yashima, M., Saito, M., Nakano, H., Takata, T., Ogisu, K., Domen, K.: Imma perovskite-type oxynitride LaTiO2N: structure and electron density, Chem. Comm., 46, 4704 – 6, (2010).
10 Jansen, M., Letschert, H. P.: Inorganic yellow-red pigments without toxic metals, Nature, 404, 980 – 82, (2000).
Copyright
Göller Verlag GmbH