Software Developer's Kit - ChemDraw

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ImplicitHydrogensAllowed Property
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Member of ChemDraw Control.Atom.

Sets and returns whether implicit hydrogens are allowed on the atom.

Property type

Read-write property


Visual Basic
Public Property ImplicitHydrogensAllowed() As Boolean

Return Type



The ImplicitHydrogensAllowed property specifies whether additional, implicit hydrogen atoms may be attached to the selected atoms.  If implicit hydrogen atoms are not allowed, all valences to that atom must be filled by bonds to non-hydrogen atoms.

This property is used when making queries.  If implicit hydrogens are not allowed, the atom may not match a target atom that has any attached hydrogens.

  • True: Allowed (default). Finds compounds regardless of whether hydrogen atoms are attached to the selected atoms.
  • False: Not allowed. Finds compounds with no additional hydrogen atoms attached to the selected atoms.


'Declares variables
 Dim myAtom As ChemDrawControl10Ctl.Atom
'Checks that there is an atom loaded in the variable
 If  Selection.Atoms.Count < 1 Then
     Exit Sub
 End If

'Checks if True/False this property
 Private sub cmdImplicitHydrogensAllowed_click()
 If  myAtom.ImplicitHydrogensAllowed = True Then
         Text1.Text = "Atom is ImplicitHydrogensAllowed"
         Text1.Text = "Atom is not ImplicitHydrogensAllowed"
     End If
 End Sub 

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