Abstract: An equation: δ_cal=250.0+Δo+Δm+Δp for calculating ¹⁷O NMR chemical shifts of the carboxylic groups in substituted benzoic acids was provided. Eight substituent parameters for the equation were obtained with least-square linear regression. Experimentally measured ¹⁷O chemical shifts from 19 substituted benzoic acids were used as the test set to examine the accuracy of the calculated results. The confidence limit was found to be 99.5% and the calculating errors for 100 % of compounds were less than δ2.0 (relative errors ≤0.2 %).

Key words: ¹⁷O NMR, chemical shift, substituent effect, regression analysis, benzoic acid, carboxyl, carbonyl, hydroxyl