oxa-comb. form

Stress is usually determined by a subsequent element and vowels may be reduced accordingly; see e.g. oxathiin n.

Forms: before a vowel frequently ox-.

Origin: Formed within English, by derivation. Etymons: oxy- comb. form², English -a-.

Etymology: < oxy- comb. form² + -a-.Attested in a small number of formations in the 20th cent. (compare oxathiene n., oxathiin n.).

Chemistry.

Forming names of compounds in which an oxygen atom is regarded as having replaced a methylene (—CH₂—) group.

ΚΠ

1928 Jrnl. Amer. Chem. Soc. 50 3075 In order to avoid confusion with the ordinary meanings of oxy-, thio-, azo-, etc., it is recommended that the forms oxa-, thia-, aza-, etc., be employed to indicate the presence of hetero atoms in a ring (the a being dropped before a vowel).

1995 Jrnl. Chem. Information & Computer Sci. 35 976/1 When ‘homo’, ‘nor’, or ‘seco’ co-occur with replacement terms such as ‘aza’ and ‘oxa’, the replacement prefixes are named in atom seniority order.

This entry has been updated (OED Third Edition, March 2005; most recently modified version published online December 2019).

单词	oxa-
释义	oxa-comb. form Stress is usually determined by a subsequent element and vowels may be reduced accordingly; see e.g. oxathiin n. Forms: before a vowel frequently ox-. Origin: Formed within English, by derivation. Etymons: oxy- comb. form², English -a-. Etymology: < oxy- comb. form² + -a-.Attested in a small number of formations in the 20th cent. (compare oxathiene n., oxathiin n.). Chemistry. Forming names of compounds in which an oxygen atom is regarded as having replaced a methylene (—CH₂—) group. ΚΠ 1928 Jrnl. Amer. Chem. Soc. 50 3075 In order to avoid confusion with the ordinary meanings of oxy-, thio-, azo-, etc., it is recommended that the forms oxa-, thia-, aza-, etc., be employed to indicate the presence of hetero atoms in a ring (the a being dropped before a vowel). 1995 Jrnl. Chem. Information & Computer Sci. 35 976/1 When ‘homo’, ‘nor’, or ‘seco’ co-occur with replacement terms such as ‘aza’ and ‘oxa’, the replacement prefixes are named in atom seniority order. This entry has been updated (OED Third Edition, March 2005; most recently modified version published online December 2019). < comb. form1928
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