We report the synthesis and structure of a molecular {Gd 7 } cage of the formula ( i Pr 2 NH 2 ) 6 [Gd 7 ( m 3 -OH) 3 (CO 3 ) 6 (O 2 C t Bu) 12 ] which has crystallographic C 3h symmetry. Low temperature speci fi c heat and adiabatic demagnetization experiments (the latter achieving temperatures below 100 mK), lead to the observation of the e ff ects of both intramolecular dipolar interactions and geometric spin frustration. The dipolar interaction leads to a massive rearrangement of energy levels such that speci fi c heat and entropy below 2 K are strongly modi fi ed while magnetic susceptibility and magnetization above 2 K are not a ff ected. The consequences of these phenomena for low temperature magnetocaloric applications are discussed.