The molar enthalpies of solution of sodium in methanol, ethanol, and n-propanol and of sodium alkoxides in their corresponding alcohols were measured at T = 298.15 K using an isoperibol solution calorimeter. From these results and other auxiliary data, the standard molar enthalpies of formation Delta H-f(m)degrees (RONa, cr) of sodium methoxide, sodium ethoxide, and sodium n-propoxide were calculated and found to be {(-366.21 +/- 11.38), (-413.39 +/- 1.45), and (-441.57 +/- 1.18)) kJ . mol(-1), respectively. A linear correlation has been found between Delta H-f(m)degrees,(RONa) and Delta H-f(m)degrees(ROH) for R = n-alkyl, enabling the prediction of data for other sodium alkoxides. (c) 2006 Elsevier Ltd. All rights reserved.