7830
From an electrospray ionization source that produces an initial distribution of Mg ( 2 + ) ( H2O ) x complexes in which x = 7 - 10 , complexes down to x = 3 are formed by using an in - source fragmentation technique .
 Chemical: Mg ( 2 + ) ( H2O ) x
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
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Answer:
 Chemical: Mg ( 2 + ) ( H2O ) x