benzenes such as 1 4 dihydroxy 2 5 dichlorobenzene 1 4 dihydroxy 3 methylbenzene etc and dihydroxy diphenyl sulfoxides such as bis 4 hydroxyphenyl sulfoixde bis 3 5 dibromo 4 hydroxyphenyl sulfoxide etc a variety of additional dihydric phenols are also available to provide carbonate polymers such as are disclosed in u s pat nos 2 999 835 3 028 365 and 3 153 008 also suitable for preparing the aromatic carbonate polymers are copolymers prepared from the above dihydric phenols copolymerized with halogen containing dihydric phenols such as 2 2 bis 3 5 dichloro 4 hydroxyphenyl propane 2 2 bis 3 5 dibromo 4 hydroxyphenyl propane etc it is also possible to employ two or more different dihydric phenols or a copolymer of a dihydric phenol with a glycol or with hydroxy or acid terminated polyester or with a dibasic acid in the event a carbonate copolymer or interpolymer rather than a homopolymer is desired for use in the preparation of the aromatic polycarbonates of this invention as well as blends of any of the above materials the carbonate precursor can be either a carbonyl halide a carbonate ester or a haloformate the carbonyl halides which can be employed are carbonyl bromide carbonyl chloride and mixtures thereof typical of the carbonate esters that.