A new microporous aluminophosphate, named Mu-13 of chemical formula Al 9 0 P 9 0 O 3 6 0 .6(K22) 2 + .12(OH) - .11H 2 O, was synthesized hydrothermally in the presence of 1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (''Kryptofix22'') as a structuring agent. Mu-13 represents a new structure type among the materials of the AlPO 4 family. Structure determination from powder data revealed a clathrate-like framework structure, the access to the microporosity being only possible through four- and six-membered rings. The biprotonated Kryptofix22 cation and two hydroxide anions are occluded in the new large [6 2 0 4 6 ] cage. The unit cell parameters are a=17.283(2) 9, c=38.913(4) 9 and V=10066.4(19) 9 3 and the space group is R-3c. Mu-13 was also characterized by SEM, TG/DTA, and 2 7 Al, 3 1 P MAS NMR, 1 3 C CP MAS and liquid NMR and chemical analysis.