valency

名词 valency:

1. the phenomenon of forming chemical bonds
2. (biology) a relative capacity to unite or react or interact as with antigens or a biological substrate
   同义词：valence
3. (chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
   同义词：valence

1. Carbon has 4 valencies.
   碳的化合价是四价。