The Discovering of Rapid Formation La(OH)₃ from LaH₃

It was found that the single crystal of LaH₃ specimen with $${Fm\overline{3}m}$$ (No.225) will decompose into powders within 24 h, which is later characterized to be La(OH)₃ by single crystal X-ray diffraction (SXRD) measurements. The discovery motivates the examination of three possible transition paths by comparing formation enthalpy with first-principles calculations and employing a custom- designed hydrogen detection setup. Furthermore, the most suitable adsorption position of O₂ molecules on the (111) surfaces has been investigated by comparing the adsorption enthalpy from different candidate positions by utilizing first-principles calculations, implying the pivotal role of O₂ molecules played in the rapid formation of La(OH)₃ along the optimal transition path.