MICROWAVE HYDROTHERMAL SYNTHESIS OF ABi
2
O
6
(A Mg, Zn)
N. Kumada
1
*, N. Kinomura
1
, and S. Komarneni
2
1
Faculty of Engineering, Yamanashi University, Miyamae-cho 7, Kofu 400 Japan
2
Materials Research Laboratory, The Pennsylvania State University,
University Park, PA 16802 USA
(Refereed)
(Received December 2, 1997; Accepted January 13, 1998)
ABSTRACT
Microwave hydrothermal processing was used to prepare two bismuth oxides,
ABi
2
O
6
(A = Mg, Zn) with the unusual oxidation state of Bi
5+
, which were
previously prepared under the limited hydrothermal conditions only. In this
work microwave hydrothermal processing for these bismuth oxides was com-
pared with conventional ones. It was found that microwave hydrothermal
processing was of greater advantage in kinetics than conventional hydrother-
mal processing. © 1998 Elsevier Science Ltd
KEYWORDS: A. oxides, C. X-ray diffraction
INTRODUCTION
Microwave hydrothermal processing has been confirmed to be of greater advantage in
kinetics than conventional hydrothermal processing for preparation of various oxides [1–5].
Hydrothermal processing can yield novel phases that cannot be prepared by high-temperature
solid-state reaction. For example, several new bismuth oxides, Bi
2
O
4
[6], LiBiO
3
[7], and
ABi
2
O
6
(A = Mg, Zn) [8] with unusual oxidation state (Bi
5+
) were prepared only under the
hydrothermal condition below 140°C, using NaBiO
3
nH
2
O as a starting material. We at-
tempted to apply microwave hydrothermal processing to the preparation of the unusual
bismuth oxides, ABi
2
O
6
(A = Mg, Zn) with the trirutile-type structure.
*To whom correspondence should be addressed.
Materials Research Bulletin, Vol. 33, No. 9, pp. 1411–1414, 1998
Copyright © 1998 Elsevier Science Ltd
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