- [sup 81]Br and [sup 35]Cl NMR yields, respectively, bromide and chloride site-specific information pertinent to the structural and electronic properties of Na[sub 8-n-p]Ag[sub n]X[sub 2-p]-sodalite, semiconductor cluster supralattices, where X = Br, Cl; 0 [le] n [le] 8; 0 [le] p [le] 2. The [sup 81]Br and [sup 35]Cl MAS chemical shifts and line shapes observed for encapsulated Na[sub 4]X and Ag[sub 4]X clusters within the sodalite cavities provide insight into the nature of the intracluster bonding (ionic-covalent character) and the extent of intercavity coupling. Substantial nuclear shielding is observed for encapsulated Ag[sub 4]X clusters in sodalite materials with high loading of Ag[sub 4]Br clusters, whereas no NMR signal is detected from silver-bromide clusters isolated within sodalite lattices. Spin-lattice and spin-spin relaxation measurements yield information on intracavity coupling and motion within the sodalite cages. The results enable one to explore the transition from isolated clusters to an expanded Ag[sub 4]X supralattice, through the compositional and temperature dependence of the NMR spectra of the sodalite halide anions. 22 refs., 10 figs.