The crystal structures of two forms of alclometasone dipropionate have been solved and refined using a single synchrotron X-ray powder diffraction pattern and optimized using density functional techniques. Both forms crystallize in the space group P212121 (#19) with Z = 4. The lattice parameters of Form 1 are a = 10.44805(7), b = 14.68762(8), c = 17.31713(9) Å, and V = 2657.44(2) Å3, and those of Form 2 are a = 10.69019(13), b = 14.66136(23), c = 17.17602(23) Å, and V = 2692.05(5) Å3. Both density functional theory and molecular mechanics optimizations indicate that Form 2 is lower in energy, but the differences are within the expected uncertainties of such calculations. In both forms, the only traditional hydrogen bond is between the hydroxyl group and the ketone in the steroid A ring. The chlorine atom acts as an acceptor in two intramolecular C–H⋯Cl hydrogen bonds involving ring hydrogens, as well as in an intermolecular hydrogen bond involving a methyl group. There are several C–H⋯O hydrogen bonds, mainly to ketone oxygens, but also to the hydroxyl group and an ether oxygen. The powder patterns have been submitted to ICDD for inclusion in the Powder Diffraction File™.

中文翻译：

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两种多晶型阿氯米松二丙酸酯的晶体结构，C28H37ClO7

两种形式的阿氯米松二丙酸酯的晶体结构已使用单一同步加速器 X 射线粉末衍射图进行求解和改进，并使用密度泛函技术进行优化。两种形式都在空间群中结晶磷212121(#19) 与Z= 4. Form 1的晶格参数为一种= 10.44805(7),b= 14.68762(8),C= 17.31713(9) Å，和五= 2657.44(2) Å3，而表格 2 的那些是一种= 10.69019(13),b= 14.66136(23),C= 17.17602(23) Å，和五= 2692.05(5) Å3. 密度泛函理论和分子力学优化均表明形式 2 的能量较低，但差异在此类计算的预期不确定性范围内。在这两种形式中，唯一的传统氢键是在类固醇 A 环中的羟基和酮之间。氯原子在涉及​​环氢的两个分子内 C-H⋯Cl 氢键以及涉及甲基的分子间氢键中充当受体。有几个C-H⋯O氢键，主要是酮氧，也有羟基和醚氧。粉末图案已提交给 ICDD，以纳入粉末衍射文件™。