22762
Addition of Ca ( 2 + ) " on - demand " allowed us to obtain homogeneous alginate ( ALG ) gels using concentrated initial ALG solutions ( 10 % ) , not possible with other ionic gelation approaches .
 Chemical: Ca ( 2 + )
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: Ca ( 2 + ) 
Answer:
 Chemical: Ca ( 2 + )