Motivated by experimental observations and chemical intuition that the degree of backbonding between a metal site and adsorbent may influence NMR chemical shifts, we first formulated a DFT protocol to probe the magnitude of backbonding for C2H4 in various chemical environments using state-of-the art energy decomposition analysis (EDA). Similar EDA techniques have been used recently to delineate forward-and back-donating contributions for H2 binding to Cu(I) in MFU-4l, and to a V(II) center in a different MOF. Here we calculate the quantitative contributions of σ(C=C), π(C=C), and σ(C-H) to σ11, σ22, σ33, and δiso in six metal complexes and three molecules: