# Question 49034

Mar 12, 2016

Actinium(III) oxide.

#### Explanation:

Actinium(III) hydroxide, "Ac"("OH")_3#, will decompose upon heating to form water and actinium(III) oxide, ${\text{Ac"_2"O}}_{3}$.

Just like the hydroxide, the oxide contains actinium in its $+ 3$ oxidation state.

The balanced chemical equation for this decomposition reaction looks like this

$2 {\text{Ac"("OH")_text(3(s]) stackrel(color(red)(Delta)color(white)(aa))(->) "Ac"_2"O"_text(3(s]) + 3"H"_2"O}}_{\textrm{\left(g\right]}}$

The symbol $\textcolor{red}{\Delta}$ is used to symbolize the fact that the reaction requires heat.