Thermodynamics of the Evaporation of Yttrium Tribromide in the Form of YBr3 and Y2Br6 Molecules

Gas-Phase Thermochemistry of MX3 and M2X6 (M = Sc, Y; X = F, Cl, Br, I) from a Composite Reaction-Based Approach: Homolytic versus Heterolytic Cleavage

“…The most recent experimental-based Δ H f °(0 K) and Δ H f °(298.15 K) estimates for YI 3 turned out to be more negative by 0.8–1.4 kcal/mol than our predicted values. All of our enthalpies of formation are within the experimental uncertainty of ±2.9 kcal/mol.…”

“…The IVTANTHERMO 17,21,22 -tabulated ΔH f °(0 K) and ΔH f °(298.15 K) values for YBr 3 are reasonably close to our predicted values, which turned out to be 2.0−2.9 kcal/mol more positive. An effect of including the 3s 2 3p 6 electrons on bromine in the correlation treatment reduced the reaction energies of eqs 1−3 by 2.3, 2, and 1.3 kcal/mol.…”

“…Our predicted Y2Br6 ΔH f °(0 K) and ΔH f °(298.15 K) are within 0.8 kcal/mol of the recent experimental estimate of Osina and co-workers. 17 An effect of correlating of the 3s 2 3p 6 Br electrons was found to be -5.3, -4.6, and -3.3 kcal/mol for Eq. 1, 2, and 3 0 K reaction enthalpies.…”

“…This deviation is within the experimental uncertainty of ±2.9 kcal/mol. The most recent 17 An effect of correlating of the 3s 2 3p 6 electrons on bromine was found to be −5.3, −4.6, and −3.3 kcal/mol for the 0 K reaction enthalpies of eqs 1−3. Similarly, a very good agreement between the predicted and experimental ΔH f °(0 K) and ΔH f °(298.15 K) values 18 was also obtained for Y 2 I 6 .…”

“…The thermal constants of substances (TCS) online database developed at the Glushko Thermocenter includes gas-phase data on the ScF 3 , ScCl 3 , ScBr 3 , Sc 2 Cl 6 , YF 3 , YCl 3 , and Y 2 Cl 6 species, although many of them are based on the experimental measurements of limited accuracy. A series of new density functional theory (DFT) and ab initio calculations performed on par with a critical analysis of the available experimental and theoretical structural data on the scandium/yttrium trihalides and their dimers resulted in refined values of the formation enthalpies of ScF 3 –ScBr 3 and Y 2 Cl 6 and afforded, for the first time, accurate thermochemistry of ScI 3 , YBr 3 , Y 2 Br 6 , YI 3 , Y 2 I 6 , and Y 2 F 6 . , These data were then incorporated in an IVTANTERMO database. , However, because many of the original data forming a basis of an IVTANTERMO database are based on the half-century-ago experimental measurements with custom-built techniques, a separate independent source of information is of paramount importance.…”