A molecular bowl with barium ion covering one portal of decamethylcucurbit[5]uril as a 'metal-ion-bottom' has been synthesized. The structure of the molecular bowl has been confirmed by the single crystal X-ray diffraction determination. It belongs to orthorhombic with space group of Pna2(1). The crystal unit cell parameters are: a=3.2108(6) nm, b=1.4742(3) nm, c=1.151 6(2) run, and V=5.4509(18) nm(3), D-c=1.677 Mg(.)m(3), Z=4, F(000)= 2832, R=0.0551, wR=0.1568
