The relativistic methods yield mean errors of less than 0.5 kcal/mol and with distribution spans of only around 1 kcal/mol ranging from approx. 0-1 kcal/mol error for the DLPNO based relativistic methods. It can be seen that there is a high degree of agreement between DKH-CCSD(T) and the reference method of ZORA-CCSD(T). Therefore relativistic methods are required for electronic energy corrections, with either DKH-DLPNO-CCSD(T 0 )