The complex Green operator G on CR manifolds is the inverse of the Kohn-Laplacian square(b) on the orthogonal complement of its kernel. In this note, we prove Schatten and Sobolev estimates for G on the unit sphere S2n-1 subset of C-n. We obtain these estimates by using the spectrum of square(b) and the asymptotics of the eigenvalues of the usual Laplace-Beltrami operator.