The crystal structure of a hydrogen sulfide sorption complex of partially Co(II)-exchanged zeolite A, Co(4)Na(4)A . 11H(2)S (a = 12.149(2) Angstrom) has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm (3) over bar m at 21(1) degrees C. The crystal of Co4Na4-A (initially light pink) was dehydrated at 380 degrees C and 2 x 10(-6) Ton for 2 days (deep blue), followed by exposure to ca. 700 Ton. of hydrogen sulfide gas at room temperature (black). The structure was refined to the final error indices R(1) = 0.055 and R(W) = 0.051 with 171 reflections for which I > 3 sigma(I). Four Co(II) ions are found at 6-oxygen ring sites where each coordinates to three framework oxygens at 2.24(1) Angstrom. Each Co(II) ion is recessed 0.65 Angstrom into the large cavity from the (111) plane of the nearest framework oxygens and coordinates at 2.60(2) Angstrom to one H2S sulfur in the large cavity. Each of four Na+ ions lies between a 4-ring and an 8-ring in the large cavity, where it coordinates to a framework oxygen at 2.75 Angstrom and to an H2S sulfur in the large cavity at 2.87 Angstrom. Each of three additional H2S molecules is near the center of an 8-oxygen ring, where it coordinates to one or two Na+ ions and "hydrogen bonds" with 8-ring oxygens.