Structure of β-trimyristin and β-tristearin from high-resolution X-ray powder diffraction data

The crystal structures of beta -1,2,3-tritetradecanoylglycerol (beta -trimyristin or beta -MMM) and beta -1,2,3-trioctadecanoylglycerol (beta -tristearin or beta -SSS) have been determined from high-resolution synchrotron X-ray powder diffraction data. Grid search and Rietveld refinement have been used to determine and refine the structure, respectively. Both substances crystallize in space group P (1) over bar with Z = 2. The unit-cell parameters for beta -MMM are a = 12.0626 (6), b = 41.714 (1), c = 5.4588 (3) Angstrom, alpha = 73.388 (4), beta = 100.408 (5) and gamma = 118.274 (4)degrees. For beta -SSS the unit-cell parameters are a = 12.0053 (7), b = 51.902 (2), c = 5.4450 (3) Angstrom, alpha = 73.752 (5), beta = 100.256 (6) and gamma = 117.691 (5)degrees. Soft-distance restraints have been applied to the molecules during refinement. For beta -MMM the final R-p value obtained is 0.053 and for beta -SSS the final R-p value is 0.041.