A new family of protonated oxides HLnTiO{sub 4} (Ln = La, Nd, Sm, and Gd)
- Kyung Hee Univ. (Korea, Republic of)
A new series of well crystallized HLnTiO{sub 4} (Ln = La, Nd, Sm, and Gd) and hydrated HLaTiO{sub 4} {center_dot} xH{sub 2}O were synthesized by Na{sup +}/H{sup +} exchange of NaLnTiO{sub 4} in 0.1 N HNO{sub 3} solutions. This protonated oxide retains the parent layered structure (P4/nmm), the layers being separated by H{sup +} ions occupying nine-coordinated Na{sup +} sites and adjacent blocks having the staggered conformation. Due to the relative displacements of proton layers on hydration, on the contrary, a doubling of c axis was observed in hydrated type HLaTiO{sub 4} {center_dot} xH{sub 2}O (x {approximately} 0.4). Thermal behaviors examined by thermogravimetric analyses showed that the interlayer protons are lost below 600{degrees}C as water. Further heating above the dehydration temperature led to LnTiO{sub 3.5} which still contained perovskite layers. They transformed into corresponding pyrochlores Ln{sub 2}Ti{sub 2}O{sub 7} from around 950{degrees}C.
- OSTI ID:
- 555037
- Journal Information:
- Journal of Solid State Chemistry, Vol. 127, Issue 1; Other Information: PBD: 15 Nov 1996
- Country of Publication:
- United States
- Language:
- English
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