Ca2Ta2TiO8

High-Entropy Materials HEA

MP-ID: mp-1045947 · Space group: C2/c (#15)

Materials Project API

Basic Information

Formula

Ca2Ta2TiO8

MP-ID

mp-1045947

Elements

Sites

Density

6.2847

g/cm³

Volume

326.53

Å³

Cell a

9.9212

Cell b

9.9212

Cell c

5.4696

α Angle

88.72

β Angle

88.72

γ Angle

37.35

Space Group

C2/c

Point Group

2/m

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
9.41	9.3963	8.3	(1,1,0)
14.72	6.0189	67.5	(1,0,0)
18.89	4.6981	78.8	(2,2,0)
19.90	4.4607	40.5	(2,1,0)
21.88	4.0625	63.6	(1,0,1)
22.04	4.0321	40.3	(1,0,-1)
25.56	3.4852	18.2	(2,1,1)
25.99	3.4284	25.7	(2,1,-1)
27.57	3.2349	76.4	(3,2,0)
28.09	3.1768	10.1	(1,-1,0)
28.50	3.1321	6.1	(3,3,0)
31.86	2.8092	88.3	(3,2,1)
32.44	2.7597	73.9	(3,2,-1)
32.60	2.7469	100.0	(1,-1,1)
32.76	2.7340	61.5	(0,0,2)
33.89	2.6450	3.4	(2,0,1)
34.07	2.6316	2.4	(3,1,0)
35.98	2.4964	6.2	(1,0,2)
36.19	2.4822	5.0	(1,0,-2)
37.67	2.3876	21.0	(2,2,2)
37.74	2.3836	8.8	(3,1,1)
38.15	2.3592	50.3	(3,1,-1)
38.32	2.3491	4.6	(4,4,0)
38.32	2.3486	1.1	(2,1,2)

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Energy Properties

Formation Energy/atom

-3.24789

eV/atom

Energy/atom

-9.03437

eV/atom

Energy above Hull

0.1551

eV/atom

Uncorrected Energy

-8.6116

eV/atom

Volume/atom

12.56

Å³

c/a Ratio

0.5513

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

4.0058

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.012270

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.615

Element Family

Metalloid-Nonmetal

Solute Fraction

0.385

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0720

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.9127

J/mol·K

Ω Parameter

0.2256

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

53.563%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0489

smaller = more stable mixing

VEC

3.846

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-34.011

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7733

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaachnif aaadzakb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1045947

Reference Citation

The crystal structure and related material properties of Ca2Ta2TiO8 were obtained from the Materials Project database (MP-ID: mp-1045947, 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_Ca2Ta2TiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.92121875
_cell_length_b   9.92121875
_cell_length_c   5.46956763
_cell_angle_alpha   88.72132524
_cell_angle_beta   88.72132524
_cell_angle_gamma   37.35005015
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2Ta2TiO8
_chemical_formula_sum   'Ca4 Ta4 Ti2 O16'
_cell_volume   326.53097643
_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
  Ca  Ca0  1  0.88670000  0.52677500  0.75546900  1.0
  Ca  Ca1  1  0.47322500  0.11330000  0.74453100  1.0
  Ca  Ca2  1  0.11330000  0.47322500  0.24453100  1.0
  Ca  Ca3  1  0.52677500  0.88670000  0.25546900  1.0
  Ta  Ta4  1  0.03536600  0.74281200  0.76102100  1.0
  Ta  Ta5  1  0.25718800  0.96463400  0.73897800  1.0
  Ta  Ta6  1  0.96463400  0.25718800  0.23897800  1.0
  Ta  Ta7  1  0.74281200  0.03536600  0.26102200  1.0
  Ti  Ti8  1  0.61575600  0.38424400  0.75000000  1.0
  Ti  Ti9  1  0.38424400  0.61575600  0.25000000  1.0
  O  O10  1  0.06793000  0.79418700  0.09831300  1.0
  O  O11  1  0.20581300  0.93207000  0.40168700  1.0
  O  O12  1  0.93207000  0.20581300  0.90168700  1.0
  O  O13  1  0.79418700  0.06793000  0.59831300  1.0
  O  O14  1  0.29836800  0.59077500  0.58285100  1.0
  O  O15  1  0.40922500  0.70163200  0.91714900  1.0
  O  O16  1  0.70163200  0.40922500  0.41714900  1.0
  O  O17  1  0.59077500  0.29836800  0.08285100  1.0
  O  O18  1  0.88076700  0.76027500  0.49424400  1.0
  O  O19  1  0.23972500  0.11923300  0.00575600  1.0
  O  O20  1  0.47061700  0.16019000  0.33956600  1.0
  O  O21  1  0.83981000  0.52938300  0.16043400  1.0
  O  O22  1  0.52938300  0.83981000  0.66043400  1.0
  O  O23  1  0.16019000  0.47061700  0.83956600  1.0
  O  O24  1  0.76027500  0.88076700  0.99424400  1.0
  O  O25  1  0.11923300  0.23972500  0.50575600  1.0

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