diff --git a/src/aiidalab_qe/app/configuration/basic/basic.py b/src/aiidalab_qe/app/configuration/basic/basic.py
index 6976e298d..57e25d037 100644
--- a/src/aiidalab_qe/app/configuration/basic/basic.py
+++ b/src/aiidalab_qe/app/configuration/basic/basic.py
@@ -45,6 +45,10 @@ def render(self):
             (self._model, "spin_type"),
             (self.spin_type, "value"),
         )
+        self.spin_type.observe(
+            self._on_spin_type_change,
+            "value",
+        )
 
         # Spin-Orbit calculation
         self.spin_orbit = ipw.ToggleButtons(style={"description_width": "initial"})
@@ -68,6 +72,29 @@ def render(self):
             (self.protocol, "value"),
         )
 
+        self.warning = ipw.HTML(
+            value="""
+                <div
+                    class="alert alert-warning"
+                    style="line-height: 140%; margin: 10px 0 0"
+                >
+                    <p>
+                        <b>Warning:</b> detected multiples atoms with different tags.
+                        You may be interested in an antiferromagnetic system. Note that
+                        default starting magnetic moments do not distinguish tagged
+                        atoms and are set to the same value.
+                    </p>
+                    <p>
+                        Please go to <b>Advanced settings</b> and override the default
+                        values, specifying appropriate starting magnetization for each
+                        species (e.g. with different signs for an antiferromagnetic
+                        configuration).
+                    </p>
+                </div>
+            """,
+            layout=ipw.Layout(display="none"),
+        )
+
         self.children = [
             InAppGuide(identifier="basic-settings"),
             ipw.HTML("""
@@ -140,9 +167,16 @@ def render(self):
                     (at the price of longer/costlier calculations).
                 </div>
             """),
+            self.warning,
         ]
 
         self.rendered = True
 
     def _on_input_structure_change(self, _):
         self.refresh(specific="structure")
+
+    def _on_spin_type_change(self, _):
+        if self._model.spin_type == "collinear" and self._model.has_tags:
+            self.warning.layout.display = "flex"
+        else:
+            self.warning.layout.display = "none"
diff --git a/src/aiidalab_qe/app/configuration/basic/model.py b/src/aiidalab_qe/app/configuration/basic/model.py
index e9e826741..f526e547d 100644
--- a/src/aiidalab_qe/app/configuration/basic/model.py
+++ b/src/aiidalab_qe/app/configuration/basic/model.py
@@ -1,13 +1,16 @@
 import traitlets as tl
 
-from aiida import orm
 from aiidalab_qe.app.parameters import DEFAULT_PARAMETERS
+from aiidalab_qe.common.mixins import HasInputStructure
 from aiidalab_qe.common.panel import ConfigurationSettingsModel
 
 DEFAULT: dict = DEFAULT_PARAMETERS  # type: ignore
 
 
-class BasicConfigurationSettingsModel(ConfigurationSettingsModel):
+class BasicConfigurationSettingsModel(
+    ConfigurationSettingsModel,
+    HasInputStructure,
+):
     title = "Basic settings"
     identifier = "workchain"
 
@@ -15,8 +18,6 @@ class BasicConfigurationSettingsModel(ConfigurationSettingsModel):
         "input_structure",
     ]
 
-    input_structure = tl.Union([tl.Instance(orm.StructureData)], allow_none=True)
-
     protocol_options = tl.List(
         trait=tl.Tuple(tl.Unicode(), tl.Unicode()),
         default_value=[
diff --git a/src/aiidalab_qe/common/mixins.py b/src/aiidalab_qe/common/mixins.py
index fa43a1632..e6629a3e4 100644
--- a/src/aiidalab_qe/common/mixins.py
+++ b/src/aiidalab_qe/common/mixins.py
@@ -26,6 +26,13 @@ def has_structure(self):
     def has_pbc(self):
         return not self.has_structure or any(self.input_structure.pbc)
 
+    @property
+    def has_tags(self):
+        return any(
+            not kind_name.isalpha()
+            for kind_name in self.input_structure.get_kind_names()
+        )
+
 
 class HasModels(t.Generic[T]):
     def __init__(self):