Basic Information
Formula
Tm3SiSe2
MP-ID
mp-3250911
Elements
3
Sites
6
Density
8.2690
g/cm³
Volume
139.13
ų
Cell a
7.0058
Å
Cell b
7.0058
Å
Cell c
7.0058
Å
α Angle
146.53
°
β Angle
132.25
°
γ Angle
59.57
°
Space Group
Immm
Point Group
mmm
Crystal System
Orthorhombic
Bravais Lattice
oI
Stability
Yes
Packing Fraction
-
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 24)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 17.25 | 5.1396 | 1.0 | (0,1,-1) |
| 23.23 | 3.8295 | 1.4 | (1,0,-1) |
| 23.23 | 3.8295 | 1.4 | (0,1,0) |
| 27.04 | 3.2977 | 39.6 | (1,2,-2) |
| 27.12 | 3.2876 | 41.0 | (1,-1,0) |
| 29.38 | 3.0402 | 2.1 | (2,2,-2) |
| 30.92 | 2.8919 | 5.5 | (1,1,-2) |
| 31.28 | 2.8597 | 68.4 | (2,1,-2) |
| 31.28 | 2.8597 | 68.4 | (1,2,-1) |
| 31.55 | 2.8355 | 68.2 | (1,-1,1) |
| 39.55 | 2.2788 | 1.4 | (2,-1,0) |
| 40.35 | 2.2353 | 4.1 | (2,3,-3) |
| 43.65 | 2.0736 | 1.5 | (1,3,-3) |
| 44.71 | 2.0268 | 24.0 | (3,3,-3) |
| 44.93 | 2.0174 | 25.7 | (1,-1,-1) |
| 45.02 | 2.0135 | 100.0 | (1,2,-3) |
| 53.08 | 1.7253 | 5.7 | (3,3,-4) |
| 53.08 | 1.7253 | 5.7 | (2,4,-3) |
| 53.23 | 1.7209 | 12.9 | (3,0,-2) |
| 53.49 | 1.7132 | 6.4 | (0,3,-3) |
| 53.53 | 1.7118 | 6.6 | (2,-2,1) |
| 55.75 | 1.6489 | 25.0 | (2,4,-4) |
| 55.79 | 1.6477 | 1.0 | (0,2,-3) |
| 55.94 | 1.6438 | 26.9 | (2,-2,0) |
Energy Properties
Formation Energy/atom
-1.69053
eV/atom
Energy/atom
-25.48387
eV/atom
Energy above Hull
0.0000
eV/atom
Uncorrected Energy
-25.4839
eV/atom
Volume/atom
23.19
ų
c/a Ratio
1.0000
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
No
Total Mag. Moment
0.0000
μB
Mag. Ordering
NM
Mag. Sites
0
Magnetization/Volume
0.000000
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Tm · 0.500
Element Family
Lanthanide
Solute Fraction
0.500
Interstitial Fraction
0.167
Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0114
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.4088
J/mol·K
Ω Parameter
0.0000
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
20.418%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.5834
smaller = more stable mixing
VEC
8.500
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9206
SS Former
0
Phase Tendency
IM
Related Tasks
Related computation task IDs (1)
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-3250911
Reference Citation
The crystal structure and related material properties of Tm3SiSe2 were obtained from the Materials Project database (MP-ID: mp-3250911, 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
Loading 3D structure…
Style: Ball & Stick
|
Drag to rotate · Scroll to zoom · Right-click to pan
Raw CIF Data
# generated using pymatgen
data_Tm3SiSe2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 7.00576831
_cell_length_b 7.00576807
_cell_length_c 7.00576837
_cell_angle_alpha 146.52789610
_cell_angle_beta 132.25128042
_cell_angle_gamma 59.56651314
_symmetry_Int_Tables_number 1
_chemical_formula_structural Tm3SiSe2
_chemical_formula_sum 'Tm3 Si1 Se2'
_cell_volume 139.12565016
_cell_formula_units_Z 1
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
Tm Tm0 1 0.84393572 0.34393572 0.50000000 1.0
Tm Tm1 1 0.50000000 0.00000000 0.50000000 1.0
Tm Tm2 1 0.15606428 0.65606428 0.50000000 1.0
Si Si3 1 0.00000000 0.00000000 0.00000000 1.0
Se Se4 1 0.66955352 0.66955352 1.00000000 1.0
Se Se5 1 0.33044648 0.33044648 0.00000000 1.0
