Water adducts of 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, tris(4,7-diphenyl-1,10-phenanthroline) Fe(II) perchlorate, tris(4,7-diphenyl-1,10-phenanthroline) Ru(II) chloride, tris(1,10-phenanthroline) Fe(II) perchlorate, and bis(2,9-dimethyl-1,10-phenanthroline) Cu(I) perchlorate had 5.1 ± 0.9, 0 ± 1.3, 6.8 ± 0.6, 5.6 ± 1.5, 4.8 ± 0.7, 6.3 ± 0.6, and 6.5 ± 1.0 molecules of H2O, respectively, associated with them when they were extracted into nitromethane. All deviations are at the 95% C.I.