Sr2TiAlCu2O7

High-Entropy Materials HEA

MP-ID: mp-1046756 · Space group: Cc (#9)

Materials Project API

Basic Information

Formula

Sr2TiAlCu2O7

MP-ID

mp-1046756

Elements

Sites

Density

4.5542

g/cm³

Volume

356.72

Å³

Cell a

5.4314

Cell b

5.7451

Cell c

12.1000

α Angle

103.79

β Angle

102.99

γ Angle

89.99

Space Group

Point Group

Crystal System

Monoclinic

Bravais Lattice

Stability

Packing Fraction

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 24)

2θ	d (Å)	I	hkl
7.73	11.4320	86.7	(0,0,1)
15.50	5.7160	4.0	(0,0,2)
19.34	4.5900	4.4	(0,1,-2)
19.36	4.5853	4.6	(0,1,1)
23.84	3.7321	3.8	(1,1,-2)
23.85	3.7310	3.4	(1,-1,1)
23.86	3.7299	3.6	(1,-1,-1)
23.86	3.7299	3.2	(1,1,0)
24.87	3.5797	9.1	(0,1,-3)
24.90	3.5760	9.1	(0,1,2)
27.45	3.2494	38.7	(1,1,-3)
27.46	3.2484	41.2	(1,-1,2)
27.47	3.2469	39.0	(1,-1,-2)
27.47	3.2465	41.3	(1,1,1)
31.14	2.8725	100.0	(0,2,-1)
31.49	2.8407	1.3	(0,1,-4)
31.52	2.8382	1.3	(0,1,3)
32.14	2.7852	1.1	(0,2,0)
32.65	2.7428	27.1	(1,1,-4)
32.66	2.7420	24.6	(1,-1,3)
32.67	2.7407	26.4	(1,-1,-3)
32.68	2.7402	24.1	(1,1,2)
32.98	2.7157	96.4	(2,0,-1)
34.94	2.5677	4.0	(0,2,-3)

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Energy Properties

Formation Energy/atom

-2.57730

eV/atom

Energy/atom

-7.02808

eV/atom

Energy above Hull

0.1865

eV/atom

Uncorrected Energy

-6.6582

eV/atom

Volume/atom

13.72

Å³

c/a Ratio

2.2278

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.1553

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000440

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.538

Element Family

Metalloid-Nonmetal

Solute Fraction

0.462

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3039

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

10.8404

J/mol·K

Ω Parameter

0.1962

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

50.421%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0156

smaller = more stable mixing

VEC

4.692

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-34.320

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8101

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaachomp aaaeasfq

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1046756

Reference Citation

The crystal structure and related material properties of Sr2TiAlCu2O7 were obtained from the Materials Project database (MP-ID: mp-1046756, database version v2026.04.13).

Literature Citation

Horton, M.K., Huck, P., Yang, R.X. et al. Accelerated data-driven materials science with the Materials Project. Nat. Mater. 24, 1522–1532 (2025). https://doi.org/10.1038/s41563-025-02272-0

3D Crystal Structure Rendering

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Raw CIF Data

# generated using pymatgen
data_Sr2TiAlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.43139682
_cell_length_b   5.74507032
_cell_length_c   12.09999046
_cell_angle_alpha   103.79378233
_cell_angle_beta   102.99084998
_cell_angle_gamma   89.99164380
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr2TiAlCu2O7
_chemical_formula_sum   'Sr4 Ti2 Al2 Cu4 O14'
_cell_volume   356.72109056
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.36238200  0.33443400  0.72053900  1.0
  Sr  Sr1  1  0.63682600  0.67139400  0.27994700  1.0
  Sr  Sr2  1  0.86311000  0.88980300  0.72079500  1.0
  Sr  Sr3  1  0.13795800  0.10873800  0.28015600  1.0
  Ti  Ti4  1  0.28079100  0.67642100  0.50025000  1.0
  Ti  Ti5  1  0.78141900  0.32595800  0.50043000  1.0
  Al  Al6  1  0.98395500  0.99348400  0.00051700  1.0
  Al  Al7  1  0.48340200  0.51096700  0.00024000  1.0
  Cu  Cu8  1  0.43415800  0.94410500  0.89035800  1.0
  Cu  Cu9  1  0.53947500  0.07001200  0.11055200  1.0
  Cu  Cu10  1  0.93350500  0.45022200  0.89021200  1.0
  Cu  Cu11  1  0.03911100  0.54333700  0.11030800  1.0
  O  O12  1  0.12752500  0.38011700  0.50053500  1.0
  O  O13  1  0.62676300  0.62211800  0.50036300  1.0
  O  O14  1  0.25148200  0.28493800  0.89297100  1.0
  O  O15  1  0.34629300  0.72254100  0.10847600  1.0
  O  O16  1  0.75181900  0.11127800  0.89314600  1.0
  O  O17  1  0.84648500  0.88900200  0.10818100  1.0
  O  O18  1  0.61199400  0.61019900  0.88934900  1.0
  O  O19  1  0.71169500  0.39897600  0.11018600  1.0
  O  O20  1  0.11322300  0.78335100  0.88967800  1.0
  O  O21  1  0.21229600  0.21494300  0.11099900  1.0
  O  O22  1  0.26832900  0.88182800  0.63419200  1.0
  O  O23  1  0.63375200  0.12105500  0.36722000  1.0
  O  O24  1  0.77016900  0.25613000  0.63481500  1.0
  O  O25  1  0.13236000  0.74599200  0.36667100  1.0

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