Since 1891 lighting lamps have been manufactured in the Netherlands. The improvement today in comparison to the first lamp is enormous , especially with the intorduction of the gas discharge lamps. The life- time has increased by orders of magnitude . the colour is also an important aspect. Rare earth metal compunds like `CeBr_(3)` are now included to reach a colour temperature of 6000K in the lamp the compounds are ionic solids at room temperature , and upon heating they sublime partially to give a vapour of neutral metal halide molecules . To achieve a high vapour pressure, the sublimation enthalpy should be as low as possible. Give the reaction equations of the thermochemical cycle (Law of Hess) for this process in which some steps involve `CeBr_(4)^(-)` ions monmelecular ions and /or neutral molecules in the phase. Step 1: `overset(+H_(1))rarr" "+` Step 2 : `+" "overset(+H_(2)) rarr` Step 3 : `+" "overset(+H_(3))rarr` Step 4: `+" "overset(+H_(4))rarr` Total : `(CsCeBr_(4))_("lattice") overset(+H_("total"))rarr` `(CeBr_(3))_("molecules") + (CsBr)_("molecules")`