(Ferrocenylmethyl)phosphane (1)o xidation with hydrogen peroxide, elemental sulfur and grey selenium produced (ferrocenylmethyl)phosphane oxide 1O,s ulfide 1S and selenide 1Se,r espectively,a st he first isolable primary phosphane chalcogenides lacking stericp rotection. At elevated temperatures, compound 1O disproportionated into 1 and (ferrocenylmethyl)phosphinic acid.I nr eactions with [(h 6-mes)RuCl 2 ] 2 , 1O underwent tautomerization into ap hosphanec omplex [(h 6-mes)RuCl 2 {FcCH 2 PH(OH)-kP}],w hereas 1S and 1Se lost their P-bound chalcogen atoms, giving rise to the phosphane complex [(h 6-mes)-RuCl 2 (FcCH 2 PH 2-kP)] (Fc = ferrocenyl, mes = mesitylene). No tautomerization was observed in the reactiono f1O with B(C 6 F 5) 3 ,w hich insteadp roduced aL ewis pair FcCH 2 P(O)H 2-B(C 6 F 5) 3 .P hosphane oxide 1O added to C=O bonds of aldehydes and ketonesa nd even to cumulenes PhNCE (E = Oa nd S). However,b oth PH hydrogens were only employed in the reactions with aldehydes and cyanates. Scheme1.Synthesis of P-chalcogenides 1E.