The dichloropalladium chelates 2a and 2b were made by treatment of [PdCl2(NCPh)2] with 1a respectively and the crystal structure of 2a, as determined by X-ray crystallog-raphy, is illustrated in Fig. 1. The bulk of the phospha-adamantane diphosphines is evident and the estimated cone angle10 is 173 (CF. 155 FOR bUT2 pch2ch2CH2PBut2 in its PtCl2 complex11); furthermore there is no possibility of