Journal of Chemical Thermodynamics, Vol.31, No.10, 1337-1345, 1999
The standard enthalpies of formation of uranium compounds. XV. Strontium uranates
Enthalpies of solution of the uranates of strontium have been measured calorimetrically in 5.075 mol . dm(-3) HCl(aq), or in (1.00 mol . dm(-3) HCl + 0.0470 mol . dm(-3) FeCl3)(aq). The results have been combined with auxiliary values to derive the standard molar enthalpies at T = 298.15 K. With the results obtained and recalculated values from the literature, the following values for Delta(f)H(m)(o)/kJ . mol(-1) have been obtained: Sr3U11O36, -(15900 +/- 17); Sr2U3O11, -(5236.4 +/-4.8); beta-SrUO4, -(1985.1 +/- 1.4); Sr5U3O14, -(7265.8 +/-7.5); Sr2UO5, -(2626.9 =/- 2.0); Sr3UO6, -(3252.4 +/- 2.1); Sr2UO4.5, -(2488.0 +/- 2.5).