Supplier Page from Thermo Fisher Scientific for Calcium sulfide, 99.9% (metals basis excluding Sr), Sr typically 500 ppm
1-Ethynyl-1-cyclohexanol, 99+% from Thermo Fisher Scientific
Ethyl (ethoxymethylene)cyanoacetate, 98% from Thermo Fisher Scientific
Ethyl 2-mercaptoacetate, 99% from Thermo Fisher Scientific
Ethyl acetoacetate, 99%, pure from Thermo Fisher Scientific