  ° C ▁in ▁air ▁for ▁one ▁hour ▁followed ▁by ▁ ▁hours ▁at ▁ 5 2 0   ° C ▁under ▁arg on . ▁If ▁the ▁presence ▁of ▁other ▁an ions ▁is ▁sus pected , ▁the ▁de h yd r ation ▁may ▁be ▁effect u ated ▁by ▁fusion ▁under ▁hydro gen ▁ch lor ide . ▁ ▁Rad ium ▁ch lor ide ▁can ▁also ▁be ▁prepared ▁by ▁he ating ▁rad ium ▁b rom ide ▁in ▁a ▁flow ▁of ▁dry ▁hydro gen ▁ch lor ide ▁gas , ▁or ▁can ▁be ▁isolated ▁from ▁u ran ium ▁and ▁thor ium ▁or es ▁ ▁by ▁tre ating ▁rad ium ▁sul f ate ▁with ▁sod ium ▁carbon ate , le aving ▁rad ium ▁carbon ate ▁and ▁then ▁react ing ▁the ▁rad ium ▁carbon ate ▁in ▁hydro ch lor ic ▁acid . ▁ ▁Properties ▁Rad ium ▁ch lor ide ▁is ▁a ▁color less - white ▁salt ▁with ▁a ▁blue - green ▁lum ines c ence , ▁especially ▁when ▁he ated . ▁Its ▁color ▁gradually ▁changes ▁to ▁yellow ▁with ▁ag ing , ▁whereas ▁cont am ination ▁by ▁b arium ▁may ▁im part ▁a ▁rose ▁t int . ▁It ▁is ▁less ▁sol ub le ▁in ▁water ▁than ▁other ▁al kal ine ▁earth ▁metal ▁ch lor ides ▁– ▁at ▁ 2 5   ° C ▁its ▁sol ub ility ▁is ▁ 2 4 5   g / L ▁whereas ▁that ▁of ▁b arium ▁ch lor ide ▁is ▁ 3 0 7 ▁g / L , ▁and ▁the ▁difference ▁is ▁even ▁larger ▁in ▁hydro