diff --git a/structuretoolkit/analyse/symmetry.py b/structuretoolkit/analyse/symmetry.py
index 1b50938fa..393011703 100644
--- a/structuretoolkit/analyse/symmetry.py
+++ b/structuretoolkit/analyse/symmetry.py
@@ -3,6 +3,7 @@
 # Distributed under the terms of "New BSD License", see the LICENSE file.
 
 import ast
+import dataclasses
 import string
 from functools import cached_property
 from typing import Optional
@@ -65,8 +66,8 @@ def __init__(
         self._angle_tolerance = angle_tolerance
         self.epsilon = epsilon
         self._permutations = None
-        for k, v in self._get_symmetry(
-            symprec=symprec, angle_tolerance=angle_tolerance
+        for k, v in dataclasses.asdict(
+            self._get_symmetry(symprec=symprec, angle_tolerance=angle_tolerance)
         ).items():
             self[k] = v