Low-temperature reaction of Aurivillius phases with halides

Article abstract of DOI:10.1006/jssc.2000.8638

Kijima et al. [T. Kijima, S. Kimura, Y. Kawahara, K. Ohe, M. Yada, and M. Machida, J. Solid State Chem. 146, 60 (1999)] recently reported a reaction between Bi₄Ti3O₁₂ and LiI in the presence of iodine at 350°C. Their product was never obtained free of Bi₄Ti₃O₁₂, but their claim was that their product was Bi₄Ti₃O₁₂ intercalated with I and Li. We have repeated this reaction and found conditions under which the reaction goes to completion, i.e., Bi₄Ti₃O₁₂ is completely consumed. The dominant crystalline product is apparently identical to the product reported by Kijima et al. However, we conclude that no intercalation of Bi₄Ti₃O₁₂ has occurred. This dominant crystalline phase is in fact BiOI. The remainder of the product is poorly crystalline. Analogous reactions occur at low temperature using other halides such as NaCl and other Aurivillius phases such as Bi₂WO₆. (C) 2000 Academic Press.

Full text of DOI:10.1006/jssc.2000.8638

Journal of Solid State Chemistry 150, 416 (2000)
doi:10.1006/jssc.2000.8638, available online at http://www.idealibrary.com on
RAPID COMMUNICATION
Low-Temperature Reaction of Aurivillius Phases with Halides
U. Sitharaman and A. W. Sleightꢀ
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003
Received December 10, 1999; accepted January 20, 2000
washed with water and dried at room temperature. In all
Kijima et al. [T. Kijima, S. Kimura, Y. Kawahara, K. Ohe, cases, the X-ray di!raction spectra of the products were
M. Yada, and M. Machida, J. Solid State Chem. 146, 60 (1999)]
recently reported a reaction between Bi4Ti3O12 and LiI in the
presence of iodine at 3503C. Their product was never obtained
free of Bi4Ti3O12, but their claim was that their product was
Bi4Ti3O12 intercalated with I and Li. We have repeated this
reaction and found conditions under which the reaction goes to
completion, i.e., Bi4Ti3O12 is completely consumed. The domi-
nant crystalline product is apparently identical to the product
reported by Kijima et al. However, we conclude that no intercala-
tion of Bi4Ti3O12 has occurred. This dominant crystalline phase is
in fact BiOI. The remainder of the product is poorly crystalline.
dominated by the highly crystalline pattern of BiOI. For
reaction temperatures of 400 and 4403C, weak peaks of
Li TiO became apparent. When the reaction temperature
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was 5503C, the peaks of Li TiO became more pronounced.
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The data presented by Kijima et al. (1) in their Fig. 3 and
Table 1 are also consistent with a dominant product of
BiOI.
Analogous reactions between Bi WO and LiI were con-
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ducted at 350, 400, and 5503C. Again, the X-ray powder
di!raction spectra were always dominated by the pattern of
Analogous reactions occur at low temperature using other hali- highly crystalline BiOI. However, peaks of Li W O were
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des such as NaCl and other Aurivillius phases such as Bi2WO6.
( 2000 Academic Press
also generally observed. Reactions under similar conditions
of Bi Ti O and Bi WO with other AX halides (A"Li,
Na, or Ag; X"Cl, Br, or I) also gave BiOX as the domi-
nant crystalline product. Other Aurivillius phases such as
Bi CaNb O , Bi NbTiO , and Bi V O reacted with LiI
at low temperatures to give BiOI as the dominant crystal-
line product.
We conclude that Aurivillius phases are generally highly
reactive with many halides at low temperature to produce
a highly crystalline BiOX phase. The other reaction prod-
ucts are generally noncrystalline or poorly crystalline. No
indication of an intercalation reaction with Aurivillius
phases was observed in any case.
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Reactions were conducted in evacuated sealed Pyrex
tubes heated at 300 to 5503C for 3 to 5 days. Reactants were
Bi O (Alfa 99.975%), TiO (Baker 99.99%), WO (Cerac
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99.99%), and LiI (Alfa 98#%). To prepare Bi Ti O and
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Bi WO , appropriate amounts of Bi O were mixed by
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grinding together with TiO or WO . These were heated at
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8253C for 2 to 3 days with intermediate grinding. The
X-ray di!raction patterns of these products showed only
Bi Ti O and Bi WO to be present.
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Initial reactions of Bi Ti O and Bi WO with LiI were
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ACKNOWLEDGMENT
conducted with and without addition of iodine. The prod-
ucts obtained were identical with or without iodine; thus,
iodine was excluded in subsequent experiments. One mole
of Bi Ti O was reacted with 4 to 8 mol of LiI at 300, 350,
This work was supported by NSF Grant DMR-9802488.
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400, 440, and 5503C for 3 to 5 days. The products were
REFERENCES
ꢀ To whom correspondence should be addressed. E-mail: sleighta@ 1. T. Kijima, S. Kimura, Y. Kawahara, K. Ohe, M. Yada, and M. Machida,
chem.orst.edu.
J. Solid State Chem. 146, 60 (1999).
416
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