> as lemmas

1875 Jrnl. Chem. Soc. 28 862 The author [sc. J. H. van't Hoff] proceeds to show that combinations which possess an atom of carbon combined with four different univalent groups, and which he terms an asymmetric atom, present anomalies with respect to isomerism.

1881 Nature 12 May 41/1 One asymmetric carbon atom, i.e. an atom directly united with four different radicles.

1885 Encycl. Brit. XIX. 314/2 A carbon atom combined with four different atoms or compound radicals may therefore be called an asymmetric carbon atom.

1902 Encycl. Brit. XXVI. 722/1 The number of modifications of an asymmetric compound—which is not itself symmetric—is 2ⁿ, where n is the number of such carbon atoms.

1904 Jrnl. Physical Chem. 8 528 By asymmetric synthesis is meant the synthesis of a substance containing an asymmetric carbon under such conditions that there shall be formed an excess either of the dextrorotatory or of the lævorotatory compound.

1949 Thorpe's Dict. Appl. Chem. IX. 117/2 A molecule containing one asymmetric carbon atom possesses two isomeric structures, which are mirror images of each other.

1949 Thorpe's Dict. Appl. Chem. IX. 118/1 Asymmetric syntheses involving photochemical reactions under the influence of circularly polarised light have been successfully attempted.

1962 P. J. Durrant & B. Durrant Introd. Adv. Inorg. Chem. viii. 237 A rotating molecule may..be regarded as a spinning top, and on this analogy a polyatomic molecule may be placed in one of the four following classes: a. Symmetric tops. b. Spherical tops. c. Linear molecules. d. Asymmetric tops.