diff --git a/src/mp_api/routes/materials/models/__init__.py b/src/mp_api/routes/materials/models/__init__.py
deleted file mode 100644
index dc25bd5e..00000000
--- a/src/mp_api/routes/materials/models/__init__.py
+++ /dev/null
@@ -1,12 +0,0 @@
-from mp_api.routes.materials.models.core import (
-    Composition,
-    Lattice,
-    Specie,
-    SiteSpecie,
-    SiteElement,
-    Site,
-    PeriodicSite,
-    Structure,
-    Status,
-    CrystalSystem,
-)
diff --git a/src/mp_api/routes/materials/models/core.py b/src/mp_api/routes/materials/models/core.py
deleted file mode 100644
index 60a4c9fb..00000000
--- a/src/mp_api/routes/materials/models/core.py
+++ /dev/null
@@ -1,121 +0,0 @@
-from typing import Dict, List, Optional, Union, Tuple
-from pydantic import BaseModel, Field
-from pymatgen.core.periodic_table import Element
-from enum import Enum
-
-Vector3D = Tuple[float, float, float]
-
-
-class Lattice(BaseModel):
-    """
-    A lattice object represented as a 3x3 matrix of floats in Angstroms
-    """
-
-    a: float = Field(..., title="*a* lattice parameter")
-    alpha: int = Field(..., title="Angle between a and b lattice vectors")
-    b: float = Field(..., title="b lattice parameter")
-    beta: int = Field(..., title="Angle between a and c lattice vectors")
-    c: float = Field(..., title="c lattice parameter")
-    gamma: int = Field(..., title="Angle between b and c lattice vectors")
-    volume: float = Field(..., title="Lattice volume")
-
-    matrix: Tuple[Vector3D, Vector3D, Vector3D] = Field(
-        ..., description="Matrix representation of this lattice"
-    )
-
-
-class Specie(BaseModel):
-    """
-    An extension of Element with an oxidation state and other optional
-    properties. Properties associated with Specie should be "idealized"
-    values, not calculated values. For example, high-spin Fe2+ may be
-    assigned an idealized spin of +5, but an actual Fe2+ site may be
-    calculated to have a magmom of +4.5. Calculated properties should be
-    assigned to Site objects, and not Specie.
-    """
-
-    symbol: str = Field(..., title="Element Symbol")
-    oxidation_state: float = Field(..., title="Oxidation State")
-    properties: Optional[Dict] = Field(..., title="Species Properties")
-
-
-Composition = Dict[Element, float]
-Composition.__doc__ = """A dictionary mapping element to total quantity"""
-
-
-class SiteSpecie(Specie):
-    """
-    Adds site occupation to Species
-    """
-
-    occu: float = Field(..., title="Occupation")
-
-
-class SiteElement(BaseModel):
-    """
-    Elements defined on site with an occupation
-    """
-
-    element: Element = Field(..., title="Element")
-    occu: float = Field(..., title="Occupation")
-
-
-class Site(BaseModel):
-    """
-    A generalized *non-periodic* site. This is essentially a composition
-    at a point in space, with some optional properties associated with it. A
-    Composition is used to represent the atoms and occupancy, which allows for
-    disordered site representation. Coords are given in standard cartesian
-    coordinates.
-    """
-
-    species: List[Union[SiteElement, SiteSpecie]] = Field(..., title="Species")
-    xyz: Tuple[float, float, float] = Field(..., title="Cartesian Coordinates")
-    label: str = Field(..., title="Label")
-    properties: Optional[Dict] = Field(None, title="Properties")
-
-
-class PeriodicSite(Site):
-    """
-    A generalized *periodic* site. This adds on fractional coordinates within the
-    lattice to the generalized Site model
-    """
-
-    abc: Tuple[float, float, float] = Field(..., title="Fractional Coordinates")
-
-
-class Structure(BaseModel):
-    """
-    Basic Structure object with periodicity. Essentially a sequence
-    of Sites having a common lattice and a total charge.
-    """
-
-    charge: Optional[float] = Field(None, title="Total charge")
-    lattice: Lattice = Field(..., title="Lattice for this structure")
-    sites: List[PeriodicSite] = Field(..., title="List of sites in this structure")
-
-    class Config:
-        extra = "allow"
-
-
-class Status(Enum):
-    """
-    """
-
-    exp = "Experimental"
-    theo = "Theoretical"
-    deprecated = "Deprecated"
-
-
-class CrystalSystem(Enum):
-    """
-    The crystal system of the lattice
-    """
-
-    tri = "triclinic"
-    mono = "monoclinic"
-    ortho = "orthorhombic"
-    tet = "tetragonal"
-    trig = "trigonal"
-    hex = "hexagonal"
-    cubic = "cubic"
diff --git a/src/mp_api/routes/materials/models/doc.py b/src/mp_api/routes/materials/models/doc.py
deleted file mode 100644
index 93c8474c..00000000
--- a/src/mp_api/routes/materials/models/doc.py
+++ /dev/null
@@ -1,177 +0,0 @@
-from typing import List
-from monty.json import MontyDecoder
-from pydantic import BaseModel, Field, validator
-from pymatgen.core.periodic_table import Element
-from datetime import datetime
-from mp_api.routes.materials.models import CrystalSystem
-from pymatgen.core.structure import Structure
-from mp_api.routes.materials.models import Composition
-
-
-class SymmetryData(BaseModel):
-    """
-    Defines a symmetry data set for materials documents
-    """
-
-    crystal_system: CrystalSystem = Field(
-        None, title="Crystal System", description="The crystal system for this lattice"
-    )
-
-    symbol: str = Field(
-        None,
-        title="Space Group Symbol",
-        description="The spacegroup symbol for the lattice",
-    )
-
-    number: int = Field(
-        None,
-        title="Space Group Number",
-        description="The spacegroup number for the lattice",
-    )
-
-    point_group: str = Field(
-        None, title="Point Group Symbol", description="The point group for the lattice"
-    )
-
-    symprec: float = Field(
-        None,
-        title="Symmetry Finding Precision",
-        description="The precision given to spglib to determine the symmetry of this lattice",
-    )
-
-    version: str = Field(None, title="SPGLib version")
-
-
-class MaterialsCoreDoc(BaseModel):
-    """
-    Basic information about a material such as its crystal structure and associated calculations.
-    """
-
-    structure: Structure = Field(
-        None, description="The lowest energy structure for this material"
-    )
-
-    initial_structures: List[Structure] = Field(
-        None,
-        description="Initial structures used in the DFT optimizations corresponding to this material",
-    )
-
-    task_id: str = Field(
-        None,
-        description="The ID of this material, used as a universal reference across property documents."
-        "This comes in the form: mp-******",
-    )
-
-    last_updated: datetime = Field(
-        None,
-        description="Timestamp for the most recent calculation for this Material document",
-    )
-
-    created_at: datetime = Field(
-        None,
-        description="Timestamp for the first calculation for this Material document",
-    )
-
-    # Structure metadata
-    nsites: int = Field(None, description="Total number of sites in the structure")
-    elements: List[Element] = Field(
-        None, description="List of elements in the material"
-    )
-    nelements: int = Field(None, title="Number of Elements")
-    composition: Composition = Field(
-        None, description="Full composition for the material"
-    )
-    composition_reduced: Composition = Field(
-        None,
-        title="Reduced Composition",
-        description="Simplified representation of the composition",
-    )
-    formula_pretty: str = Field(
-        None,
-        title="Pretty Formula",
-        description="Cleaned representation of the formula",
-    )
-    formula_anonymous: str = Field(
-        None,
-        title="Anonymous Formula",
-        description="Anonymized representation of the formula",
-    )
-    chemsys: str = Field(
-        None,
-        title="Chemical System",
-        description="dash-delimited string of elements in the material",
-    )
-    volume: float = Field(
-        None,
-        title="Volume",
-        description="Total volume for this structure in Angstroms^3"
-        # TODO Should be normalize to the formula unit?
-    )
-
-    density: float = Field(
-        None, title="Density", description="Density in grams per cm^3"
-    )
-
-    density_atomic: float = Field(
-        None,
-        title="Packing Density",
-        description="The atomic packing density in atoms per cm^3",
-    )
-
-    symmetry: SymmetryData = Field(None, description="Symmetry data for this material")
-
-    deprecated: bool = Field(
-        None, description="Whether the material is tagged as deprecated"
-    )
-
-    task_ids: List[str] = Field(
-        None, description="List of IDs for calculations associated with this material"
-    )
-
-    origins: List[dict] = Field(
-        None, description="List of IDs used to populate data for the material"
-    )
-
-    task_types: dict = Field(
-        None, description="Description of calculation type for each ID in task_ids"
-    )
-
-    # Make sure that the datetime field is properly formatted
-    @validator("last_updated", pre=True)
-    def last_updated_dict_ok(cls, v):
-        return MontyDecoder().process_decoded(v)
-
-
-class MaterialProperty(BaseModel):
-    """
-    Class defining metadata that can be applied to a property of any material
-    This metadata is used for search
-    """
-
-    # elements list for periodic table lookup
-    elements: List[Element] = Field(
-        None, description="List of elements in the material"
-    )
-    # Used to lookup formula components
-    composition_reduced: Composition = Field(
-        None,
-        title="Reduced Composition",
-        description="Simplified representation of the composition",
-    )
-
-    # Used to look up any anonymous formula
-    formula_anonymous: str = Field(
-        None,
-        title="Anonymous Formula",
-        description="Anonymized representation of the formula",
-    )
-
-    formula_pretty: str = Field(
-        None, title="Pretty Formula", description="Human readable chemical formula"
-    )
-
-    material_id: str = Field(
-        None,
-        title="Material ID",
-        description="The ID for the material this property document corresponds to",
-    )
diff --git a/src/mp_api/routes/materials/query_operators.py b/src/mp_api/routes/materials/query_operators.py
index 9da8a703..b326b459 100644
--- a/src/mp_api/routes/materials/query_operators.py
+++ b/src/mp_api/routes/materials/query_operators.py
@@ -2,7 +2,7 @@
 from fastapi import Query
 from mp_api.core.query_operator import STORE_PARAMS, QueryOperator
 from mp_api.routes.materials.utils import formula_to_criteria
-from mp_api.routes.materials.models.core import CrystalSystem
+from emmet.core.symmetry import CrystalSystem
 from pymatgen.core.periodic_table import Element
 from collections import defaultdict
 
diff --git a/src/mp_api/routes/materials/resources.py b/src/mp_api/routes/materials/resources.py
index e47ac6ec..0382011a 100644
--- a/src/mp_api/routes/materials/resources.py
+++ b/src/mp_api/routes/materials/resources.py
@@ -1,6 +1,5 @@
 from fastapi import HTTPException
 from mp_api.core.resource import GetResource
-from mp_api.routes.materials.models.core import Structure
 
 from emmet.core.material import MaterialsDoc
 
@@ -21,7 +20,7 @@
 )
 
 from pymatgen.analysis.structure_matcher import StructureMatcher, ElementComparator
-from pymatgen.core import Structure as PS
+from pymatgen.core import Structure
 from pymatgen.core import Composition
 from pymongo import MongoClient  # type: ignore
 from itertools import permutations
@@ -101,7 +100,7 @@ async def find_structure(
             """
 
             try:
-                s = PS.from_dict(structure.dict())
+                s = Structure.from_dict(structure.dict())
             except Exception:
                 raise HTTPException(
                     status_code=404,
@@ -128,7 +127,7 @@ async def find_structure(
                 criteria=crit, properties=["structure", "task_id"]
             ):
 
-                s2 = PS.from_dict(r["structure"])
+                s2 = Structure.from_dict(r["structure"])
                 matched = m.fit(s, s2)
 
                 if matched:
diff --git a/src/mp_api/routes/phonon/models.py b/src/mp_api/routes/phonon/models.py
index 9d3d57b1..3d8ffb49 100644
--- a/src/mp_api/routes/phonon/models.py
+++ b/src/mp_api/routes/phonon/models.py
@@ -3,8 +3,7 @@
 from monty.json import MontyDecoder
 
 from pydantic import BaseModel, Field, validator
-
-from mp_api.routes.materials.models.core import Structure
+from pymatgen.core import Structure
 from pymatgen.phonon.bandstructure import PhononBandStructureSymmLine
 
 
diff --git a/src/mp_api/routes/search/models.py b/src/mp_api/routes/search/models.py
index 8f01321a..bdccb8be 100644
--- a/src/mp_api/routes/search/models.py
+++ b/src/mp_api/routes/search/models.py
@@ -1,18 +1,16 @@
-from typing import List, Optional, Dict, Union
-from pymatgen.core.periodic_table import Element
-from pymatgen.core.structure import Structure
-from pymatgen.analysis.magnetism.analyzer import Ordering
+from typing import Dict, List, Optional, Union
 
-from emmet.core.mpid import MPID
 from emmet.core.electronic_structure import BandstructureData, DosData
-from emmet.core.thermo import DecompositionProduct
+from emmet.core.mpid import MPID
 from emmet.core.symmetry import SymmetryData
-
-from mp_api.routes.materials.models.doc import Composition
-from mp_api.routes.xas.models import Edge, XASType
+from emmet.core.thermo import DecompositionProduct
+from emmet.core.xas import Edge, Type
 from mp_api.routes.grain_boundary.models import GBTypeEnum
-
 from pydantic import BaseModel, Field
+from pymatgen.analysis.magnetism.analyzer import Ordering
+from pymatgen.core.composition import Composition
+from pymatgen.core.periodic_table import Element
+from pymatgen.core.structure import Structure
 
 
 class SearchStats(BaseModel):
@@ -68,7 +66,7 @@ class XASSearchData(BaseModel):
     )
     absorbing_element: Element = Field(None, title="Absorbing Element")
 
-    spectrum_type: XASType = Field(None, title="Type of XAS Spectrum")
+    spectrum_type: Type = Field(None, title="Type of XAS Spectrum")
 
 
 class GBSearchData(BaseModel):
diff --git a/src/mp_api/routes/search/resources.py b/src/mp_api/routes/search/resources.py
index 882575bf..97bf7a0d 100644
--- a/src/mp_api/routes/search/resources.py
+++ b/src/mp_api/routes/search/resources.py
@@ -1,32 +1,32 @@
 from typing import Optional
-from typing_extensions import Literal
 
 import numpy as np
+from emmet.core.search import SearchDoc
 from fastapi import Query
-from scipy.stats import gaussian_kde
-
 from mp_api.core.query_operator import PaginationQuery, SortQuery, SparseFieldsQuery
 from mp_api.core.resource import GetResource
+from mp_api.routes.electronic_structure.query_operators import ESSummaryDataQuery
 from mp_api.routes.materials.query_operators import (
+    DeprecationQuery,
     ElementsQuery,
     FormulaQuery,
     MinMaxQuery,
     SymmetryQuery,
-    DeprecationQuery,
 )
-from mp_api.routes.search.models import SearchDoc, SearchStats
+from mp_api.routes.search.models import SearchStats
 from mp_api.routes.search.query_operators import (
-    MaterialIDsSearchQuery,
     HasPropsQuery,
-    SearchIsStableQuery,
-    SearchElasticityQuery,
-    SearchMagneticQuery,
+    MaterialIDsSearchQuery,
     SearchDielectricPiezoQuery,
+    SearchElasticityQuery,
+    SearchIsStableQuery,
     SearchIsTheoreticalQuery,
+    SearchMagneticQuery,
 )
 from mp_api.routes.surface_properties.query_operators import SurfaceMinMaxQuery
-from mp_api.routes.electronic_structure.query_operators import ESSummaryDataQuery
 from mp_api.routes.thermo.query_operators import ThermoEnergyQuery
+from scipy.stats import gaussian_kde
+from typing_extensions import Literal
 
 
 def search_resource(search_store):
diff --git a/src/mp_api/routes/tasks/models.py b/src/mp_api/routes/tasks/models.py
index 7819d6e1..8a4c8dc4 100644
--- a/src/mp_api/routes/tasks/models.py
+++ b/src/mp_api/routes/tasks/models.py
@@ -6,7 +6,7 @@
 from pydantic import BaseModel, Field, validator
 
 from pymatgen.core.structure import Structure
-from mp_api.routes.materials.models import Composition
+from pymatgen.core.composition import Composition
 from pymatgen.core.periodic_table import Element
 from pymatgen.io.vasp import Incar, Poscar, Kpoints, Potcar
 from pymatgen.core.trajectory import Trajectory
diff --git a/src/mp_api/routes/xas/client.py b/src/mp_api/routes/xas/client.py
index 3d85372b..fdd3f28f 100644
--- a/src/mp_api/routes/xas/client.py
+++ b/src/mp_api/routes/xas/client.py
@@ -1,7 +1,7 @@
 from typing import List, Optional
 from pymatgen.core.periodic_table import Element
 from mp_api.core.client import BaseRester, MPRestError
-from mp_api.routes.xas.models import Edge, XASType, XASDoc
+from emmet.core.xas import Edge, Type, XASDoc
 
 
 class XASRester(BaseRester):
@@ -14,7 +14,7 @@ def get_available_elements(
         # TODO implement actual check
         self,
         edge: Optional[Edge] = None,
-        spectrum_type: Optional[XASType] = None,
+        spectrum_type: Optional[Type] = None,
         absorbing_element: Optional[Element] = None,
         required_elements: Optional[List[Element]] = None,
     ):
diff --git a/src/mp_api/routes/xas/models.py b/src/mp_api/routes/xas/models.py
deleted file mode 100644
index 01adaf37..00000000
--- a/src/mp_api/routes/xas/models.py
+++ /dev/null
@@ -1,90 +0,0 @@
-from enum import Enum
-from typing import List, Optional
-from datetime import datetime
-
-from monty.json import MontyDecoder
-from pydantic import BaseModel, Field, validator
-
-from pymatgen.core.periodic_table import Element
-from pymatgen.core.structure import Structure
-
-from mp_api.routes.materials.models.doc import MaterialProperty
-
-
-class Edge(Enum):
-    """
-    The interaction edge for XAS
-    There are 2n-1 sub-components to each edge where
-    K: n=1
-    L: n=2
-    M: n=3
-    N: n=4
-    """
-
-    K = "K"
-    L2 = "L2"
-    L3 = "L3"
-    L2_3 = "L2,3"
-
-
-class XASType(Enum):
-    """
-    Type of XAS Spectrum
-    """
-
-    XANES = "XANES"
-    EXAFS = "EXAFS"
-    XAFS = "XAFS"
-
-
-class XASSpectrum(BaseModel):
-    """
-    Spectrum Data
-    """
-
-    x: List[float] = Field(None, title="X-ray energy")
-    y: List[float] = Field(None, title="Absorption (Arbitrary Units)")
-    structure: Optional[Structure] = Field(None, title="Structure")
-    absorbing_element: Optional[Element] = Field(None, title="Absoring Element")
-    edge: Edge = Field(
-        None, title="Absorption Edge", description="The interaction edge for XAS"
-    )
-
-
-class XASDoc(MaterialProperty):
-    """
-    X-ray absorption spectra, absorption edge, absorbing element, ...
-    """
-
-    spectrum: Optional[XASSpectrum] = None
-
-    edge: Edge = Field(
-        None, title="Absorption Edge", description="The interaction edge for XAS"
-    )
-    absorbing_element: Element = Field(None, title="Absorbing Element")
-
-    spectrum_type: XASType = Field(None, title="Type of XAS Spectrum")
-
-    xas_id: str = Field(
-        None, title="XAS Document ID", description="The unique ID for this XAS document"
-    )
-
-    task_id: str = Field(
-        None, title="The material id for the material this document corresponds to"
-    )
-
-    xas_ids: List[str] = Field(
-        None,
-        title="Calculation IDs",
-        description="List of Calculations IDS used to make this XAS spectrum",
-    )
-
-    last_updated: datetime = Field(
-        None,
-        description="timestamp for the most recent calculation for this XAS spectrum",
-    )
-
-    # Make sure that the datetime field is properly formatted
-    @validator("last_updated", pre=True)
-    def last_updated_dict_ok(cls, v):
-        return MontyDecoder().process_decoded(v)
diff --git a/src/mp_api/routes/xas/query_operator.py b/src/mp_api/routes/xas/query_operator.py
index 8d77c6fc..66ac0499 100644
--- a/src/mp_api/routes/xas/query_operator.py
+++ b/src/mp_api/routes/xas/query_operator.py
@@ -1,6 +1,6 @@
 from fastapi import Query
 from mp_api.core.query_operator import STORE_PARAMS, QueryOperator
-from mp_api.routes.xas.models import Edge, XASType
+from emmet.core.xas import Edge, Type
 from pymatgen.core.periodic_table import Element
 from typing import Optional
 
@@ -9,7 +9,7 @@ class XASQuery(QueryOperator):
     def query(
         self,
         edge: Edge = Query(None, title="XAS Edge"),
-        spectrum_type: XASType = Query(None, title="Spectrum Type"),
+        spectrum_type: Type = Query(None, title="Spectrum Type"),
         absorbing_element: Element = Query(None, title="Absorbing Element"),
     ) -> STORE_PARAMS:
         """
diff --git a/src/mp_api/routes/xas/resources.py b/src/mp_api/routes/xas/resources.py
index 02510ee5..8665406c 100644
--- a/src/mp_api/routes/xas/resources.py
+++ b/src/mp_api/routes/xas/resources.py
@@ -1,5 +1,5 @@
 from mp_api.core.resource import GetResource
-from mp_api.routes.xas.models import XASDoc
+from emmet.core.xas import XASDoc
 
 from mp_api.core.query_operator import PaginationQuery, SortQuery, SparseFieldsQuery
 from mp_api.routes.materials.query_operators import ElementsQuery, FormulaQuery