• Minimum 2000kj/kg stored when cycling between at T_cold and T_hot.

• T_cold not less than 500k

• T_hot greater than T_cold but less than 1000k

• 3atm or less in a closed container. Gas phase is allowed but total density should not be less than 0.5kg/l.

• Must be able to cycle at least 10,000 times without losing more than 20% of capacity.

Full bounty will be awarded for identifying a mix of chemicals that satisfies all of these criteria and showing your work to demonstrate it satisfies the criteria. There is no partial credit.