ZnCl2 forms a 1 : 1 double salt with phosphatidylcholine. This compound resembles the long-known double salt of CdCl2 and phosphatidylcholine except that the latter has the composition (CdCl2)3(phosphatidylcholine)2. Treatment of phosphatidylcholine with a mixture of equimolar amounts of ZnCl2 and CdCl2 yields the ZnCl2 double salt. The ZnCl2 double salt can be obtained as an amorphous flocculent precipitate and as small spherules. These results are discussed in relation to the toxic action of cadmium salts on the mammalian testis and to the protection afforded by zinc salts. It is suggested that membrane phospholipids are essential components of specific sites for reversible binding of Zn2+ and Cd2+.
