Effect of Temperature on the Structure of Gaseous Molecules. Molecular Structure of PCl3 at 300° and 505°K

Publisher Website
Google Scholar
Abstract
The molecular structure of PCl3 has been studied by electron diffraction from the vapor at nozzle temperatures of 300° and 505°K. Both the size of the molecule and the displacement of the atoms during molecular vibration are found to be significantly greater at the higher temperature: The P–Cl and Cl···Cl distances are longer by 0.3 and 0.4%, respectively, and the rms amplitudes associated with these distances are greater by a striking 19 and 31%. Both the increased size of the molecule and increased amplitudes are in very good agreement with prediction from simple theory. The results at 300° and 505°K, respectively, are rP‐Cl=2.039±0.0014 A and 2.045±0.0016 A; rCl···Cl=3.130±0.0026 A and 3.142±0.0038 A; lP‐Cl=0.0501±0.0013 A and 0.0594±0.0017 A; lCl···Cl=0.0834±0.0023 A and 0.1097±0.0035 A. The interatomic distances given are ra values obtained from the third cycle of least‐squares refinement of intensity curves and differ from the equilibrium values re by small amounts; the lij values differ similarly from the le values. The estimated standard errors include standard deviations derived from the least‐squares procedure, estimates of correlation among the data, uncertainty in the constants of the experiment, and uncertainty in the factors employed in the data reduction.