These molecules are . Two ball-and-stick models of molecules, which consist of the same elements. There is a black ball in the center with one red, one white, one blue, and one green ball attached to it. The first molecule has the red ball attached to the black ball at the top left position, the blue ball attached at the bottom left, the white ball attached at the top right, and the green ball at the bottom right. The second molecule has the white ball attached to the black ball at the top left position, the green ball attached at the bottom left, the red ball attached at the top right, and the blue ball at the bottom right. thiols cis-trans isomers (geometric isomers) structural isomers enantiomers R-dopa and L-dopa