Abstract
Thulium oxide, Tm
2
O
3
, was obtained as a final product of the thermal decomposition of Tm(CH
3
COO)
3
·4H
2
O. The decomposition steps up to 800°C were characterized by TG, DTA, XRD, SEM, GC-MS and gas- and solid-phase IR spectroscopy. The results showed that Tm(CH
3
COO)
3
·4H
2
O dehydrates completely in two overlapping steps at 90 and 110°C and decomposes to Tm
2
O
3
at 540°C through a non-crystalline intermediate Tm(OH)(CH
3
COO)
2
at 350°C, Tm(O)(CH
3
COO) at 375°C and Tm
2
O
2
CO
3
at 400°C. The oxides obtained at 600 and 800°C were subjected to texture analysis and pyridine adsorption. The results revealed that the oxide obtained at 600°C has a higher surface area of 49.7 m
2
g
−1
with larger pores than that obtained at 800°C (
S
BET
=32.8 m
2
g
−1
). On the other hand, the oxide obtained at 600°C has a basic surface character and contains at least two different Lewis acid sites as indicated from pyridine adsorption. The gaseous decomposition products as identified by gas-phase IR and GC-MS are water vapour, acetic acid, ketene, acetone and methane.