diff --git a/CrystalStructure/crystal/atomic_site.py b/CrystalStructure/crystal/atomic_site.py
index 93afb34..e9da2de 100644
--- a/CrystalStructure/crystal/atomic_site.py
+++ b/CrystalStructure/crystal/atomic_site.py
@@ -32,6 +32,14 @@ class AtomicSite(Serializable):
     def __post_init__(self):
         self.atom_type : AtomType = AtomType(symbol=self.species_symbol)
 
+    @property
+    def pymatgen_species(self) -> SpeciesLike:
+        return self.atom_type.specifier
+
+    @property
+    def element_symbol(self) -> str:
+        return self.pymatgen_species.element.symbol
+
     @classmethod
     def make_void(cls) -> AtomicSite:
         return cls(x=None, y=None, z=None, occupancy=0.0, species_symbol=AtomType.void_symbol)
diff --git a/CrystalStructure/crystal/base.py b/CrystalStructure/crystal/base.py
index 38dca49..e25cabb 100644
--- a/CrystalStructure/crystal/base.py
+++ b/CrystalStructure/crystal/base.py
@@ -23,7 +23,7 @@ def __init__(self, atomic_sites : Optional[list[AtomicSite]] = None):
     def calculate_atomic_volume(self) -> float:
         total_atomic_volume = 0
         for site in self.get_non_void_sites():
-            element_symbol : str = site.species_symbol
+            element_symbol : str = site.element_symbol
             covalent_radius  = AtomicConstants.get_covalent(element_symbol=element_symbol)
             vdw_radius = AtomicConstants.get_vdw_radius(element_symbol=element_symbol)
 
diff --git a/tests/t_crystal/t_properties.py b/tests/t_crystal/t_properties.py
index 48f821c..22833d5 100644
--- a/tests/t_crystal/t_properties.py
+++ b/tests/t_crystal/t_properties.py
@@ -1,7 +1,8 @@
 import math
+from typing import Union
 
 import numpy as np
-from pymatgen.core import Lattice, Structure, Composition, PeriodicSite
+from pymatgen.core import Lattice, Structure, Composition, PeriodicSite, Site, Species, Element
 
 import tests.t_crystal.crystal_test as BaseTest
 from CrystalStructure.crystal import AtomicSite, CrystalStructure
@@ -14,16 +15,14 @@ def test_pymatgen(self):
         for struct, crystal in zip(self.pymatgen_structures, self.crystals):
             actual = self.to_clustered_pymatgen(crystal)
             expected = struct
-
             self.assertEqual(actual.lattice, expected.lattice)
 
-            print(f'Actual sites = {actual.sites}; Expected sites = {expected.sites}')
             self.assertEqual(len(actual.sites), len(expected.sites))
-
             actual_sites = sorted(actual.sites, key=dist_from_origin)
             expected_sites = sorted(expected.sites, key=dist_from_origin)
+            print(f'Expected, actual sites = {expected_sites}, {actual_sites}')
             for s1,s2 in zip(actual_sites, expected_sites):
-                self.assertEqual(s1,s2)
+                self.check_sites_equal(s1,s2)
 
             print(f'Composition = {actual.composition}')
 
@@ -59,6 +58,26 @@ def test_symmetries(self):
 
     # ---------------------------------------------------------
 
+    def check_sites_equal(self, s1 : Site, s2 : Site):
+        s1, s2 = self.standardize_site(s1), self.standardize_site(s2)
+        self.assertEqual(s1, s2)
+
+    @staticmethod
+    def standardize_site(site : Site):
+        def cast_to_species(x : Union[Species, Element]):
+            if isinstance(x, Element):
+                x = Species(symbol=str(x), oxidation_state=0)
+            return x
+
+        if isinstance(site.species, Composition):
+            comp = site.species
+            species = Composition({cast_to_species(x) : occ for x, occ in comp.items()})
+            site = Site(species=species, coords=site.coords)
+
+        return site
+
+
+
     @staticmethod
     def to_clustered_pymatgen(crystal : CrystalStructure) -> Structure:
         a, b, c = crystal.lengths.as_tuple()
@@ -85,13 +104,14 @@ def matching_cluster(the_site):
 
         site_comps = []
         for clust in clusters:
-            comp = Composition({site.atom_type: site.occupancy for site in clust})
+            comp = Composition({site.pymatgen_species : site.occupancy for site in clust})
             site_comps.append(comp)
 
         positions = [(c[0].x, c[0].y, c[0].z) for c in clusters]
         return Structure(lattice=lattice, species=site_comps, coords=positions)
 
 
+
 def dist_from_origin(site : PeriodicSite | AtomicSite):
     return math.sqrt(site.x ** 2 + site.y ** 2 + site.z ** 2)
 
diff --git a/tests/t_crystal/t_standard.py b/tests/t_crystal/t_standard.py
index 6063db2..7c9b617 100644
--- a/tests/t_crystal/t_standard.py
+++ b/tests/t_crystal/t_standard.py
@@ -35,7 +35,7 @@ def test_scaling(self):
     def test_standardization(self):
         self.mock_crystal.standardize()
         expected_species_list = ['O', 'Si', AtomType.void_symbol]
-        acrual_species_list = [site.species_symbol for site in self.mock_crystal.base]
+        acrual_species_list = [site.species_symbol1 for site in self.mock_crystal.base]
         self.assertEqual(acrual_species_list, expected_species_list)
 
         actual_primitives = self.mock_crystal.lengths.as_tuple()