The crystal structure of ractopamine hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Ractopamine hydrochloride crystallizes in space group Pbca (#61) with a = 38.5871(49), b = 10.7691(3), c = 8.4003(2) Å, V = 3490.75(41) Å3, and Z = 8. The ractopamine cation contains two chiral centers, and the sample consists of a mixture of the S,S/R,R/S,R and R,S forms. Models for the two diastereomers S,S and S,R were refined, and yielded equivalent residuals, but the S,R form is significantly lower in energy. The crystal structure consists of layers of molecules parallel to the bc-plane. In each structure one of the H atoms on the protonated N atom acts as a donor in a strong discrete N–H⋯Cl hydrogen bond. Hydroxyl groups act as donors in O–H⋯Cl and O–H⋯O hydrogen bonds. Both the classical and C–H⋯Cl and C–H⋯O hydrogen bonds differ between the forms, helping to explain the large microstrain observed for the sample. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

中文翻译：

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盐酸莱克多巴胺的晶体结构，C18H24NO3Cl

利用同步加速器X射线粉末衍射数据解析和精炼了盐酸莱克多巴胺的晶体结构，并利用密度泛函理论技术进行了优化。盐酸莱克多巴胺在空间群中结晶铅(#61) 与A= 38.5871(49),乙= 10.7691(3),C= 8.4003(2) 埃,V= 3490.75(41) 埃3， 和Z= 8. 莱克多巴胺阳离子含有两个手性中心，样品由 S,S/R,R/S,R 和 R,S 形式的混合物组成。对两种非对映异构体 S,S 和 S,R 的模型进行了改进，并产生了等效的残差，但 S,R 形式的能量明显较低。晶体结构由平行于晶体的分子层组成公元前-飞机。在每个结构中，质子化 N 原子上的一个 H 原子充当强离散 N–H⋯Cl 氢键的供体。羟基充当 O-H⋯Cl 和 O-H⋯O 氢键的供体。经典氢键、C-H⋯Cl 和 C-H⋯O 氢键的形式都不同，这有助于解释在样品中观察到的大微应变。粉末图案已提交给 ICDD® 以包含在粉末衍射文件™ (PDF®) 中。