- SINHALITE - AlMgBO₄

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) starting from an experimental structure similar to the one reported in AMCSD

Crystal Structure

Because of the translational symmetry all the calculations are performed in the primitive unit cell and not in the conventional unit cell. The following information regarding the structure is given with respect to this primitive unit cell, which sometimes can take an unintuitive shape.

Symmetry (experimental):

Space group:	62		Pnma
Lattice parameters (Å):	5.2272	3.0031		2.2903
Angles (°):	90	90		90

Symmetry (theoretical):

Space group:	62		Pnma
Lattice parameters (Å):	9.6930	5.5861		4.2718
Angles (°):	90	90		90

Cell contents:

Number of atoms:	28
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Al:	0.0000	0.0000	0.0000
Mg:	0.2750	0.2500	0.9852
B:	0.0869	0.2500	0.4090
O:	0.0809	0.2500	0.7427
O:	0.4436	0.2500	0.2552
O:	0.1494	0.0374	0.2644
Al:	0.5000	0.0000	0.5000
Mg:	0.2250	0.7500	0.4852
B:	0.4131	0.7500	0.9090
O:	0.4191	0.7500	0.2427
O:	0.0564	0.7500	0.7552
O:	0.3506	0.9626	0.7644
Al:	0.0000	0.5000	0.0000
Mg:	0.7250	0.7500	0.0148
B:	0.9131	0.7500	0.5910
O:	0.9191	0.7500	0.2573
O:	0.5564	0.7500	0.7448
O:	0.8506	0.5374	0.7356
Al:	0.5000	0.5000	0.5000
Mg:	0.7750	0.2500	0.5148
B:	0.5869	0.2500	0.0910
O:	0.5809	0.2500	0.7573
O:	0.9436	0.2500	0.2448
O:	0.6494	0.4626	0.2356
O:	0.8506	0.9626	0.7356
O:	0.6494	0.0374	0.2356
O:	0.1494	0.4626	0.2644
O:	0.3506	0.5374	0.7644

Atom type

We have listed here the reduced coordinates of all the atoms in the primitive unit cell.
It is enough to know only the position of the atoms from the assymetrical unit cell and then use the symmetry to build the whole crystal structure.

Visualization of the crystal structure:

You can define the size of the supercell to be displayed in the jmol panel as integer translations along the three crystallographic axis.
Please note that the structure is represented using the primitive cell, and not the conventional one.

Powder Raman

Powder Raman spectrum

The intensity of the Raman peaks is computed within the density-functional perturbation theory. The intensity depends on the temperature (for now fixed at 300K), frequency of the input laser (for now fixed at 21834 cm^-1, frequency of the phonon mode and the Raman tensor. The Raman tensor represents the derivative of the dielectric tensor during the atomic displacement that corresponds to the phonon vibration. The Raman tensor is related to the polarizability of a specific phonon mode.

Choose the polarization of the lasers.

I ∥

I ⊥

I Total

Horizontal:

Xmin:
Xmax:

Vertical:

Ymin:
Ymax:

Data about the phonon modes

Frequency of the transverse (TO) and longitudinal (LO) phonon modes in the zone-center. The longitudinal modes are computed along the three cartesian directions. You can visualize the atomic displacement pattern corresponding to each phonon by clicking on the appropriate cell in the table below.

1	ac	0	0	0	0
2	ac	0	0	0	0
3	ac	0	0	0	0
4	Au	136	136	136	136
5	B3u	156	159	156	156
6	B3g	226	226	226	226	7.250e+37 0.7	9.969e+37 0.9	1.722e+38 1.6
7	B1u	227	227	227	228
8	Ag	235	235	235	235	4.608e+37 0.4	1.157e+37 0.1	5.766e+37 0.5
9	Au	249	249	249	249
10	B2u	263	263	274	263
11	Au	274	274	274	274
12	B2g	278	278	278	278
13	B2u	282	282	295	282
14	Ag	296	296	296	296	5.766e+38 5.3	4.177e+37 0.4	6.183e+38 5.7
15	B1u	304	304	304	305
16	B3u	310	313	310	310
17	B1g	322	322	322	322	1.179e+38 1.1	1.621e+38 1.5	2.800e+38 2.6
18	B2u	330	330	332	330
19	B2g	332	332	341	332	8.665e+37 0.8	1.191e+38 1.1	2.058e+38 1.9
20	B1u	341	341	345	343
21	Au	363	363	363	363
22	B3g	380	380	380	380	8.674e+37 0.8	1.193e+38 1.1	2.060e+38 1.9
23	Ag	381	381	381	381	3.776e+39 35.0	2.482e+38 2.3	4.025e+39 37.3
24	B1g	388	388	388	388	5.671e+38 5.3	7.798e+38 7.2	1.347e+39 12.5
25	B2g	388	388	388	388	4.373e+37 0.4	6.013e+37 0.6	1.039e+38 1.0
26	B3u	391	407	391	391
27	Ag	407	407	407	407	1.478e+38 1.4	3.737e+37 0.3	1.852e+38 1.7
28	B3g	407	413	407	407	8.108e+37 0.8	1.115e+38 1.0	1.926e+38 1.8
29	Ag	413	417	413	413	2.074e+39 19.2	1.768e+38 1.6	2.250e+39 20.9
30	B1g	417	423	417	417	3.691e+38 3.4	5.075e+38 4.7	8.767e+38 8.1
31	B2g	423	432	423	423	6.297e+38 5.8	8.659e+38 8.0	1.496e+39 13.9
32	B1u	432	437	432	440
33	B3u	440	452	440	450
34	Au	459	459	459	459
35	B2u	459	459	461	459
36	B1g	462	462	462	462	2.278e+38 2.1	3.132e+38 2.9	5.410e+38 5.0
37	B3g	471	471	471	471
38	B2g	472	472	472	472	2.615e+38 2.4	3.595e+38 3.3	6.210e+38 5.8
39	B3u	480	480	480	480
40	B1u	484	484	484	484
41	B3u	485	487	485	485
42	B1u	487	499	487	499
43	B2u	499	500	500	500
44	Au	500	501	501	501
45	Ag	501	508	508	508	3.550e+39 32.9	1.499e+39 13.9	5.049e+39 46.8
46	B2g	508	524	524	524	2.448e+39 22.7	3.366e+39 31.2	5.814e+39 53.9
47	B1g	524	528	534	539	1.258e+38 1.2	1.730e+38 1.6	2.988e+38 2.8
48	Au	539	539	539	550
49	B2u	550	550	554	554
50	B3g	554	554	559	555	5.449e+38 5.1	7.492e+38 7.0	1.294e+39 12.0
51	B1u	559	559	570	570
52	Au	570	570	574	577
53	B3u	577	578	577	581
54	B2u	581	581	583	583
55	B3u	583	605	605	584
56	B1u	605	610	609	621
57	Ag	621	621	621	622	3.975e+39 36.9	2.630e+38 2.4	4.238e+39 39.3
58	B2g	622	622	622	626	9.222e+38 8.6	1.268e+39 11.8	2.190e+39 20.3
59	B1u	691	691	691	691
60	B3u	691	699	691	699
61	B2u	699	704	704	704
62	Au	704	707	707	707
63	B3g	707	709	709	709	1.147e+39 10.6	1.577e+39 14.6	2.723e+39 25.3
64	B1g	709	712	731	740	2.172e+38 2.0	2.986e+38 2.8	5.158e+38 4.8
65	Ag	761	761	761	761	1.049e+40 97.3	2.893e+38 2.7	1.078e+40 100.0
66	B1u	776	776	776	782
67	B3u	782	782	782	791
68	Ag	791	791	791	792	2.161e+39 20.0	1.362e+37 0.1	2.175e+39 20.2
69	B2g	792	792	792	796	8.129e+37 0.8	1.118e+38 1.0	1.931e+38 1.8
70	B2g	799	799	799	799	1.539e+36 0.0	2.116e+36 0.0	3.655e+36 0.0
71	B3u	808	820	808	808
72	B1u	820	827	820	821
73	Ag	870	870	870	870	7.892e+39 73.2	2.455e+38 2.3	8.137e+39 75.5
74	B2g	881	881	881	881	1.945e+38 1.8	2.674e+38 2.5	4.619e+38 4.3
75	B3u	909	935	909	909
76	B2u	935	957	957	935
77	B3g	957	992	992	957	1.026e+39 9.5	1.411e+39 13.1	2.437e+39 22.6
78	Au	992	1009	1009	992
79	B1g	1009	1011	1011	1009	6.803e+38 6.3	9.354e+38 8.7	1.616e+39 15.0
80	B1u	1011	1016	1060	1020
81	Ag	1060	1060	1069	1060	5.362e+39 49.7	6.115e+37 0.6	5.423e+39 50.3
82	B2g	1069	1069	1093	1069	1.031e+37 0.1	1.418e+37 0.1	2.448e+37 0.2
83	B1u	1093	1093	1103	1103
84	B3u	1103	1112	1104	1231

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥