Acta Crystallographica Section B

Structural Science

Volume 57, Part 3 (June 2001)

research papers

Acta Cryst. (2001). B57, 372-377 [ doi:10.1107/S0108768100019121 ]

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

A. van Langevelde, R. Peschar and H. Schenk

Abstract: 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 $\bar 1$ with Z = 2. The unit-cell parameters for [beta] -MMM are a = 12.0626 (6), b = 41.714 (1), c = 5.4588 (3) Å, [alpha] = 73.388 (4), [beta] = 100.408 (5) and [gamma] = 118.274 (4)°. For [beta] -SSS the unit-cell parameters are a = 12.0053 (7), b = 51.902 (2), c = 5.4450 (3) Å, [alpha] = 73.752 (5), [beta] = 100.256 (6) and [gamma] = 117.691 (5)°. 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.

Keywords: powder diffraction; triacylglycerols.