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Abstract
5-(4-n-Butylphenyl)-2-(4-Cyanophenyl)-Pyrimidine (BPCPP in short) has a very large mesomorphic range from 93.5 °C to 244.7 °C. We have reported in this paper X-ray diffraction studies of aligned sample of BPCPP over the entire Liquid crystalline range, using a camera designed by us in a magnetic field of 5.8 Kilogauss. On the basis of X-ray diffraction, texture and DTA study the substance is found to have the following phase transitions
Orientational order parameters (P 2) and (P 4) have been determined from the calculation of f(β), the orientational distribution function in the nematic range, (P 4) values agrees well with the theoretical values. Agreement of (P 2) with theoretical values is rather erratic. We are unable to explain this. Apparent molecular length L and inter molecular distances have been calculated. The molecules of BPCPP form associations in the mesophase like other cyano compounds.