diff --git a/doc/source/getting-started/quickstart.rst b/doc/source/getting-started/quickstart.rst
index 6d491cd..a2ed28d 100644
--- a/doc/source/getting-started/quickstart.rst
+++ b/doc/source/getting-started/quickstart.rst
@@ -25,7 +25,7 @@ Here is an example of building the UCCD ansatz with the H2 molecule to test your
     hamiltonian = h2.hamiltonian()
 
     # Build a UCC circuit ansatz for running VQE
-    circuit = hf_circuit(h2.nso, sum(h2.nelec))
+    circuit = hf_circuit(h2.nso, h2.nelec)
     circuit += ucc_circuit(h2.nso, [0, 1, 2, 3])
 
     # Create and run the VQE, starting with random initial parameters
diff --git a/doc/source/tutorials/ansatz.rst b/doc/source/tutorials/ansatz.rst
index ae3ff31..09b76e2 100644
--- a/doc/source/tutorials/ansatz.rst
+++ b/doc/source/tutorials/ansatz.rst
@@ -120,7 +120,7 @@ An example of how to build a UCC doubles circuit ansatz for the :math:`H_2` mole
 
     # Set parameters for the rest of the experiment
     n_qubits = mol.nso
-    n_electrons = mol.nalpha + mol.nbeta
+    n_electrons = mol.nelec
 
     # Build UCCD circuit
     circuit = hf_circuit(n_qubits, n_electrons) # Start with HF circuit
diff --git a/src/qibochem/ansatz/ucc.py b/src/qibochem/ansatz/ucc.py
index a234c1b..9888be1 100644
--- a/src/qibochem/ansatz/ucc.py
+++ b/src/qibochem/ansatz/ucc.py
@@ -300,7 +300,7 @@ def ucc_ansatz(
         Qibo ``Circuit``: Circuit corresponding to an UCC ansatz
     """
     # Get the number of electrons and spin-orbitals from the molecule argument
-    n_elec = sum(molecule.nelec) if molecule.n_active_e is None else molecule.n_active_e
+    n_elec = molecule.nelec if molecule.n_active_e is None else molecule.n_active_e
     n_orbs = molecule.nso if molecule.n_active_orbs is None else molecule.n_active_orbs
 
     # Define the excitation level to be used if no excitations given