The crystal and molecular structures of the acaricides chlorotrineophylstannane (ta), chlorotris[( dimethylphenylsilyl)methyl]stannane (tb ), and trineophyl(1,2,4-triazol-1-yl)stannane hemihydrate (2a · 0.5H 2 0), have been determined by single-crystal X-ray diffraction studies. The structure of 2,5-dimethyl-2,5-diphenylhexane (4) was also investigated for comparison.