Thulium(III) chloride or thulium trichloride is the chemical compound composed of thulium and chlorine with the formula TmCl3. It forms yellow crystals. Thulium(III) chloride has the YCl3 (AlCl3) layer structure with octahedral thulium ions.
Molar mass：275.292 g/mol
Appearance：Green Wet Crystalline Aggregates
Melting point：824 °C (1,515 °F; 1,097 K)
Solubility in water：very soluble
Solubility:：very soluble in ethanol
Thulium(III) chloride hydrate is used extremely as a rare metal to study the metal science of thulium.