diff --git a/src/rimsschemedrawer/gui.py b/src/rimsschemedrawer/gui.py
index 74dfe8b..c0eb0f3 100644
--- a/src/rimsschemedrawer/gui.py
+++ b/src/rimsschemedrawer/gui.py
@@ -873,9 +873,9 @@ def write_json(self) -> dict:
             dispforbidden = "noshow"
         savedict["settings"]["show_forbidden_transitions"] = dispforbidden
         savedict["settings"]["plot_title"] = self.edt_sett_plttitle.text()
-        savedict["settings"][
-            "show_transition_strength"
-        ] = self.chk_sett_trans_strength.isChecked()
+        savedict["settings"]["show_transition_strength"] = (
+            self.chk_sett_trans_strength.isChecked()
+        )
         savedict["settings"]["line_breaks"] = self.chk_sett_linebreaks.isChecked()
         savedict["settings"]["show_cm-1_axis"] = self.chk_sett_showcmax.isChecked()
         savedict["settings"]["show_eV_axis"] = self.chk_sett_showevax.isChecked()
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 65949c0..b3eef29 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -87,6 +87,13 @@ def test_term_to_string(vals):
     assert ut.term_to_string(vals[0]) == vals[1]
 
 
+def test_term_to_string_latex():
+    """Return a string surrounded by $ if LaTeX characters found."""
+    str_in = "^{3}F_{2}"
+    str_exp = f"${str_in}$"
+    assert ut.term_to_string(str_in) == str_exp
+
+
 @pytest.mark.parametrize("val", ["IP", "AI", "Rydberg", "Ryd"])
 def test_term_to_string_no_change(val):
     """Leave these symbols / strings unchanged."""