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

Abstract

The crystal structures of β-1,2,3-tritetradecanoylglycerol (β-trimyristin or β-MMM) and β-1,2,3-trioctadecanoylglycerol (β-tristearin or β-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\bar 1 with Z = 2. The unit-cell parameters for β-MMM are a = 12.0626 (6), b = 41.714 (1), c = 5.4588 (3) Å, α = 73.388 (4), β = 100.408 (5) and γ = 118.274 (4)°. For β-SSS the unit-cell parameters are a = 12.0053 (7), b = 51.902 (2), c = 5.4450 (3) Å, α = 73.752 (5), β = 100.256 (6) and γ = 117.691 (5)°. Soft-distance restraints have been applied to the molecules during refinement. For β-MMM the final R_p value obtained is 0.053 and for β-SSS the final R_p value is 0.041.