The structure of agr;hyphen;N2is cubic in the space groupP213 with four molecules per unit cell. A total of 49 independent observed singlehyphen;crystal xhyphen;ray diffraction maxima yieldRequals;Sgr;thinsp;Verbar;Foverbar;minus;verbar;Fcthinsp;Verbar;thinsp;sol;Sgr;verbar;Foverbar;equals;0.13. Two faint reflections, (501) and (520), violate the space groupPa3, which yieldsR=0.21. Molecular centers are displaced by 0.1 to 0.2 Aring; from the centrosymmetric positions inPa3 along the 111 directions so that the symmetry is reduced toP213.Some corrections have been made in the Lorentz factors for upper levels and for the absorption of x rays in the experimental arrangement in the bgr;hyphen;N2study. The value ofRimproves from 0.09 to 0.04 for the freely rotating model, and the best precession angle is 56.0deg; rather than 54.5deg; (both plusmn;2.5deg;) for the precession model, which we prefer.
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