Lexical Bundles in Research Articles in Chemistry: A Structural Analysis

This paper reports the results of a corpus-driven study that investigated the structural frequency and diversity of lexical bundles in chemistry research articles. The investigation was based on a corpus of 1,185 chemistry research articles, totaling four million words. WordSmith was used to generate four-word lexical bundles and their concordance lines. Altogether, 223 lexical bundles were found. More than 55% of these bundles were phrasal; 35% of them were clausal. ‘Prepositional phrases + of’ bundles were the most frequently used bundles. Bundles with a passive verb, followed by a prepositional phrase fragment were the second most frequent bundles in the entire corpus. Bundles with the structure ‘noun phrase + of’ were the third and second most frequent bundles in the corpus and among phrasal bundles, respectively. In terms of diversity, bundles with ‘noun phrase + of’ and ‘passive + prepositional phrase fragment’ were the most varied and bundles with ‘pronoun/noun phrase + be’ structure were the least varied bundles in the entire corpus. Prepositional phrase bundles outnumbered noun phrase bundles in terms of frequency, whereas noun phrase bundles outnumbered prepositional phrase bundles in diversity. Altogether, the results show that frequency and diversity correlate with the type of phrasal lexical bundle. Moreover, the study suggests that different discourses are associated with different sets of lexical bundles with different frequency and diversity, due to the different communicative functions they follow. The paper ends with implications for future EAP research, materials development, and pedagogy.