double decomposition vs metathesis

double decomposition

noun
  • a reaction between two substances in which two parts of each substance are exchanged; metathesis 

metathesis

noun
  • The double decomposition of inorganic salts. 

  • The breaking and reforming of double bonds in olefins in which substituent groups are swapped. 

  • The transposition of letters, syllables or sounds within a word, such as in ask as /æks/. 

How often have the words double decomposition and metathesis occurred in a corpus of books? (source: Google Ngram Viewer )