Reinvestigation of the molecular structure of gaseousphyphen;benzoquinone by electron diffraction

摘要

The molecular structure of gaseousphyphen;benzoquinone has been studied by electron diffraction at a nozzlehyphen;tip temperature of 110ndash;125deg;C. The molecule hasD2hsymmetry to within experimental error. The results for the more important distance (ra), bond angle, and rms amplitude (l) parameters arerCsngbnd;Hequals;1.089thinsp;Aring;thinsp;lpar;0.011rpar;,thinsp;rCdblbnd;Oequals;1.225thinsp;Aring;thinsp;lpar;0.002rpar;,thinsp;rCdblbnd;Cequals;1.344thinsp;Aring;thinsp;lpar;0.003rpar;,thinsp;rCsngbnd;Cequals;1.481thinsp;Aring;thinsp;lpar;0.002rpar;,thinsp;ang;C2C1C6equals;118.1deg;thinsp;lpar;0.3rpar;,thinsp;ang;C3C2Hequals;121.4deg;thinsp;lpar;assumedrpar;,thinsp;lCsngbnd;Hequals;0.077thinsp;Aring;thinsp;lpar;assumedrpar;,thinsp;lCdblbnd;Oequals;0.0424thinsp;Aring;thinsp;lpar;0.0020rpar;,thinsp;lCdblbnd;Cequals;0.0446thinsp;Aring;thinsp;lpar;0.0024rpar;, andlCsngbnd;Cequals;0.0546thinsp;Aring;thinsp;lpar;0.0024rpar;. These values are in good agreement with those found in an early electronhyphen;diffraction study by Swingle, and except for the length of the carbonhyphen;carbon double bond, in excellent agreement with those found in the crystal by Trotter.