One of four possible stereoisomers of a methyl(trifluoropropyl)siloxane cyclic tetramer was isolated from low molecular weight volatiles, formed in a reaction mixture during ring-opening/equilibration polymerization of methyl(3,3,3-trifluoropropyl)cyclotrisiloxane (D₃^F). The crystalline solid was recognized as resembling a previously isolated cyclic siloxane with undetermined stereochemistry, assigned as a cyclotetrasiloxane by IR spectroscopy, and then further characterized by multinuclear (¹H, ¹³C, ¹⁹F, and ²⁹Si) NMR spectroscopy as a relatively high symmetry species with respect to the potential cis–trans relationships of the methyl and 3,3,3-trifluoropropyl substituents at Si. Unambiguous characterization and assignment of the stereochemistry was accomplished by a single crystal X-ray diffraction study, which revealed the compound was the trans, trans, trans-isomer, one species in these equilibration polymerization mixtures. The single crystal X-ray structure of the related, commercially important trans-D₃^F cyclotrisiloxane has also been determined. The structures of the two cyclic fluorinated siloxanes are discussed with respect to each other, and in the context of prototypical structures for these common Si₃O₃ and Si₄O₄ ring systems.

_{从低分子量挥发物中分离出甲基（三氟丙基）硅氧烷环状四聚体的四种可能的立体异构体之一，该挥发物是在甲基（3,3,3-三氟丙基）环三硅氧烷（D 3} ^F）开环/平衡聚合过程中在反应混合物中形成的。）。该结晶固体被认为类似于先前分离的环状硅氧烷，具有未确定的立体化学，通过红外光谱指定为环四硅氧烷，然后通过多核（ 1 H、 13 C、 19 F 和²⁹ Si ^） NMR^光谱进一步^表征为相对较高的结构。Si 上的甲基和 3,3,3-三氟丙基取代基的潜在顺反关系的对称性物种。通过单晶 X 射线衍射研究完成了立体化学的明确表征和分配，结果表明该化合物是反式、反式、反式异构体，是这些平衡聚合混合物中的一种。相关的、商业上重要的反式-D ₃ ^F环三硅氧烷的单晶X射线结构也已确定。_{两种环状氟化硅氧烷的结构在这些常见的Si 3} O ₃和Si ₄ O ₄环系的原型结构的背景下相互讨论。