The crystal structure of dehydrated $Ag_{5.6}K_{6.4}-A$, zeolite A ion-exchanged with $K^+;and;Ag^+$ as indicated and dehydrated at 360$^{circ}$C, has been determined by single-crystal X-ray diffraction techniques. Also determined were the structures of the products of the reactions of this zeolite with 0.1 Torr of Cs vapor at 250$^{circ}$C for 48 h and 72 h, and with 0.1 Torr of Rb vapor at 250$^{circ}$C for 24 h. The structures were solved and refined in the cubic space group Pm3m at 21(l)$^{circ}$C (a= 12.255(l) ${AA}$ , 12.367(l) ${AA}$, 12.350(l) ${AA}$, and 12.263(l) ${AA}$, respectively). Dehydrated $Ag_{5.6}K_{6.4}$-A was refined to the final error indices $R_1= 0.044;and;R_2=0.037$ with 202 reflections for which I>3${sigma}$(I). The crystal structures of the reaction products were refined to $R_1=0.087;and;R_2= 0.089$ with 157 reflections, $R_1=0.080;and;R_2= 0.087$ with 161 reflections, and $R_1= 0.071;and;R_2=0.061$ with 88 reflections, respectively. In the structure of $Ag_{5.6}K_{6.4}-A,;K^+$ ions block all 8-oxygen rings, and one reduced Ag atom is found per sodalite cavity. Also, ca. 4.6 $Ag^+ ions;and;3.4 K^+ ions$ are found at 6-ring sites in the large cavity. The crystal structures of the reaction products show that all $K^+$ and $Ag^+$ ions have been reduced, and that all K^+$ atoms have left the zeolite. Cs or Rb species are found at three different crystallographic sites: 3.0 $Cs^+;or;3.0Rb^+$ ions per unit cell occupy 8-ring centers, ca. 8.0 $Cs^+ ions;or;5.7 Rb^+$ ions, are found on threefold axes opposite 6-rings deep in the large cavity, and ca. 2.5 $Cs^+;or;2.3 Rb^+ ions are found on threefold axes in the sodalite unit. Also, 1 $Rb^+$ ion lies opposite a 4-ring. Silver atoms, corresponding to 75% or 40% occupancy of hexasilver clusters stabilized by coordination to $Cs^+;or;Rb^+$ ions, are found at the centers of the large cavities. In the crystal structures of dehydrated Ag_{5.6}K_{6.4}-A$ reacted with Cs vapor, excess Cs atoms are absorbed and these form (locally) cationic clusters such as $(Cs_4)3^+;and;(Cs_6)4^+$.