The distributions and Xe-129 NMR chemical shifts of xenon in zeolite AgA have been measured in a series of experiments by Moudrakovski, Ratcliffe, and Ripmeester [Proc. Internat. Zeolite Conference, Quebec, 1995; unpublished]. We carry out grand canonical Monte Carlo (GCMC) simulations of xenon in a rigid zeolite AgA lattice to provide the average Xe-n cluster shifts, and the distributions P-n for comparison with their experiments. The GCMC results for the distributions, the fraction P-n of the alpha cages containing n Xe atoms, are compared with the experimental distributions in 12 samples and the agreement is excellent. The distributions in NaA and in AgA are very similar, as can be established from the comparison of the dispersion of the distributions, {[n(2)]-[n](2)}, and both are different from the idealized hypergeometric distribution, in which the component atoms occupy eight lattice sites per cage under mutual exclusion. The calculated chemical shift increments [sigma(Xe-n)-sigma(Xen-1)](AgA) are in good agreement with experiment. The differences between these and the increments in zeolite NaA, {[sigma(Xe-n)-sigma(Xen-1)](AgA) -[sigma(Xe-n)-sigma(Xen-1)](NaA)}, are fairly small and are in good agreement with experiment. The absolute Xe-129 chemical shifts of Xe-n in the alpha cages of AgA are nearly uniformly shifted by about 40 ppm compared to the Xe-n clusters in NaA. This is attributed to the Fermi contact shifts arising from the Ag-0 metal atoms that form the linear Ag-3(2+) complexes that are found within the beta cages of AgA. (C) 1997 American Institute of Physics.