Crystal structures, polymers glide plane

Studies of the crystal structure of the polymerized monolayers were undertaken using electron diffraction data.( ) The kinematic approximation could bemade, since a monolayer crystal contained only 1/2 the a-axis repeat of the normal structure of both the monomer and the polymer. The monomer structure is monoclinic with a 33° tilt of the hydrocarbon side chains (a-axis) from the be plane towards the b-axis. Thus c is the unique axis and the monolayer is 31A thick (a-axis 62A). A complete structure of the polymqr has been performed. Jhe unit ce l was orthorhqmbic with a = 70A (monolayer thickness 35A) b = 8.11A and c = 4.89A (chain axis). The monolayer contains 2 monomer repeats in 2 chains (unit cell contains 4 monomer repeats in 4 chains) related by a glide along the b-axis. The final residual was 9% indicating an excellent fit between calculated and observed intensities. 

---