21564
Analysis of the reaction progress by powder X - ray diffraction , solid - state ( 13 ) C CPMAS NMR , solid - state FTIR spectroscopy , and thermal analysis has revealed that solid - to - solid reactions proceed either through metastable phases susceptible to amorphization or by mechanisms that involve a reconstructive phase transition that culminates in the formation of the stable phase of the product .
 Chemical: ( 13 ) C
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ( 13 ) C