22896
The formaldehyde lies in the FCF plane of difluoromethane , linked through a C - HF and a bifurcated CH2O weak hydrogen bonds .
 formaldehyde, FCF, difluoromethane, C - HF, CH2O, hydrogen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 formaldehyde, FCF, difluoromethane, C - HF, CH2O, hydrogen