 For example, with hydrochloric acid, the oxide follows the reaction Er2O3 + 6 HCl → 2 ErCl3 + 3 H2O to form erbium chloride.One interesting property of erbium oxides is their ability to up convert photons.Photon upconversion takes place when infrared or visible radiation, low energy light, is converted to ultraviolet or violet radiation higher energy light via multiple transfer or absorption of energy.