title oxalate 6-311G optimization accuracy 20 7 charge -2 zmat angs x c 1 cx o 2 co 1 ocx o 2 co 1 ocx 3 180 x 1 d 2 xxc 3 90.0 c 1 cx 5 xxc 2 180.0 o 6 co 1 ocx 3 ocxo o 6 co 1 ocx 7 180.0 variables cx 0.801646 hessian 0.929882 co 1.24266 hessian 3.635572 ocx 117.056 hessian 4.852961 constants ocxo 180 d 1.0 xxc 90.0 end basis tzvp O 6-311G tzvp C 6-311G end runtype optimize vectors extguess enter 1 stop