- BRENKITE - Ca₂CO₃F₂

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:	60		Pbcn
Lattice parameters (Å):	7.6500	7.5500		6.5480
Angles (°):	90	90		90

Symmetry (theoretical):

Space group:	60		Pbcn
Lattice parameters (Å):	7.5539	7.5933		6.2748
Angles (°):	90	90		90

Cell contents:

Number of atoms:	32
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Ca:	0.3205	0.1601	0.4718
C:	0.0000	0.0224	0.2500
O:	0.0000	0.1919	0.2500
O:	0.3624	0.4403	0.3108
F:	0.3801	0.1225	0.0995
Ca:	0.1795	0.3399	0.9718
C:	0.5000	0.4776	0.7500
O:	0.5000	0.3081	0.7500
O:	0.1376	0.0597	0.8108
F:	0.1199	0.3775	0.5995
Ca:	0.6795	0.1601	0.0282
O:	0.6376	0.4403	0.1892
F:	0.6199	0.1225	0.4005
Ca:	0.8205	0.3399	0.5282
O:	0.8624	0.0597	0.6892
F:	0.8801	0.3775	0.9005
Ca:	0.6795	0.8399	0.5282
C:	0.0000	0.9776	0.7500
O:	0.0000	0.8081	0.7500
O:	0.6376	0.5597	0.6892
F:	0.6199	0.8775	0.9005
Ca:	0.8205	0.6601	0.0282
C:	0.5000	0.5224	0.2500
O:	0.5000	0.6919	0.2500
O:	0.8624	0.9403	0.1892
F:	0.8801	0.6225	0.4005
Ca:	0.3205	0.8399	0.9718
O:	0.3624	0.5597	0.8108
F:	0.3801	0.8775	0.5995
Ca:	0.1795	0.6601	0.4718
O:	0.1376	0.9403	0.3108
F:	0.1199	0.6225	0.0995

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	B3u	79	83	79	79
5	B3g	83	91	83	83	4.554e+39 9.5	6.261e+39 13.0	1.081e+40 22.5
6	B1u	91	94	91	93
7	B1g	94	114	94	94	1.239e+37 0.0	1.704e+37 0.0	2.943e+37 0.1
8	A1g	121	121	121	121	9.635e+39 20.0	5.270e+39 11.0	1.491e+40 31.0
9	Au	131	131	131	131
10	B3g	136	136	136	136	1.773e+39 3.7	2.438e+39 5.1	4.211e+39 8.8
11	B1g	142	142	142	142	3.339e+37 0.1	4.591e+37 0.1	7.930e+37 0.2
12	B3g	145	145	145	145	7.714e+36 0.0	1.061e+37 0.0	1.832e+37 0.0
13	B3u	148	148	148	148
14	B1u	163	163	163	164
15	A1g	167	167	167	167	3.857e+38 0.8	2.058e+38 0.4	5.915e+38 1.2
16	Au	170	170	170	170
17	B1g	171	171	171	171	6.090e+38 1.3	8.373e+38 1.7	1.446e+39 3.0
18	B2g	171	171	171	171	5.855e+39 12.2	8.051e+39 16.7	1.391e+40 28.9
19	B2u	172	172	173	172
20	B1u	177	177	177	178
21	B1g	183	183	183	183	3.782e+38 0.8	5.201e+38 1.1	8.983e+38 1.9
22	B3g	191	191	191	191	2.666e+39 5.5	3.666e+39 7.6	6.332e+39 13.2
23	B2g	194	194	194	194	7.585e+38 1.6	1.043e+39 2.2	1.801e+39 3.7
24	B3u	204	208	204	204
25	B1u	208	208	208	215
26	Au	215	215	215	219
27	A1g	219	219	219	222	1.795e+39 3.7	1.206e+39 2.5	3.001e+39 6.2
28	B2u	222	222	222	228
29	Au	228	228	228	232
30	A1g	232	232	232	234	1.538e+38 0.3	9.609e+37 0.2	2.499e+38 0.5
31	B3u	234	236	234	236
32	B1g	236	237	236	241	1.920e+38 0.4	2.640e+38 0.5	4.561e+38 0.9
33	B3g	241	241	241	245	4.121e+36 0.0	5.666e+36 0.0	9.787e+36 0.0
34	B2g	247	247	247	247	6.607e+36 0.0	9.084e+36 0.0	1.569e+37 0.0
35	B3u	254	254	254	254
36	B2u	258	258	258	258
37	A1g	262	262	262	262	6.304e+38 1.3	4.698e+38 1.0	1.100e+39 2.3
38	B1u	270	270	270	271
39	B1g	271	271	271	273	1.963e+39 4.1	2.699e+39 5.6	4.662e+39 9.7
40	B3g	276	276	276	276	4.208e+39 8.7	5.786e+39 12.0	9.993e+39 20.8
41	B1g	281	281	281	281	1.112e+38 0.2	1.529e+38 0.3	2.641e+38 0.5
42	Au	284	284	284	284
43	B2g	287	287	287	287	1.754e+38 0.4	2.412e+38 0.5	4.167e+38 0.9
44	B1u	288	288	288	288
45	B1u	292	292	292	300
46	B2u	300	300	300	301
47	Au	301	301	301	302
48	B3g	302	302	302	305	1.609e+37 0.0	2.212e+37 0.0	3.821e+37 0.1
49	B3u	305	309	305	309
50	A1g	309	309	309	315	2.119e+38 0.4	1.168e+38 0.2	3.287e+38 0.7
51	B3u	315	318	315	318
52	B2g	318	319	318	319	5.974e+37 0.1	8.215e+37 0.2	1.419e+38 0.3
53	B1g	319	322	319	323	2.116e+39 4.4	2.910e+39 6.0	5.026e+39 10.4
54	Au	323	323	323	327
55	B3g	327	327	327	329	1.680e+39 3.5	2.310e+39 4.8	3.990e+39 8.3
56	B3u	329	331	329	331
57	B2u	331	339	339	339
58	B2g	339	346	346	346	2.058e+38 0.4	2.829e+38 0.6	4.887e+38 1.0
59	B1g	346	346	346	346	1.268e+38 0.3	8.787e+37 0.2	2.146e+38 0.4
60	B1g	346	352	352	351	1.372e+38 0.3	9.458e+37 0.2	2.318e+38 0.5
61	B1u	352	355	358	358
62	B3g	358	358	358	359
63	B1g	359	359	359	360	2.715e+38 0.6	3.733e+38 0.8	6.448e+38 1.3
64	B2g	360	360	360	363	3.970e+36 0.0	5.458e+36 0.0	9.428e+36 0.0
65	B2u	363	363	366	366
66	A1g	366	366	366	366	6.717e+38 1.4	5.019e+38 1.0	1.174e+39 2.4
67	B1g	366	366	371	371	1.612e+38 0.3	2.216e+38 0.5	3.828e+38 0.8
68	B3u	371	376	376	376
69	B1u	376	382	382	382
70	B2g	382	389	387	389	1.095e+39 2.3	1.506e+39 3.1	2.602e+39 5.4
71	B2u	389	394	394	394
72	Au	394	462	465	404
73	B1u	708	708	708	709
74	B3u	710	710	710	710
75	B3g	711	711	711	711	2.893e+38 0.6	3.978e+38 0.8	6.872e+38 1.4
76	B1g	713	713	713	713	1.242e+39 2.6	1.708e+39 3.6	2.951e+39 6.1
77	A1g	718	718	718	718	2.010e+39 4.2	1.506e+39 3.1	3.516e+39 7.3
78	B2u	719	719	720	719
79	B2g	720	720	721	720	1.868e+38 0.4	2.569e+38 0.5	4.437e+38 0.9
80	Au	722	722	722	722
81	B1u	833	833	833	833
82	B3u	833	833	833	848
83	B1g	861	861	861	861	1.286e+38 0.3	1.768e+38 0.4	3.053e+38 0.6
84	B3g	862	862	862	862	2.813e+37 0.1	3.868e+37 0.1	6.682e+37 0.1
85	Au	1093	1093	1093	1093
86	B2u	1094	1094	1094	1094
87	A1g	1096	1096	1096	1096	4.771e+40 99.2	3.912e+38 0.8	4.810e+40 100.0
88	B2g	1097	1097	1097	1097	2.936e+38 0.6	4.037e+38 0.8	6.972e+38 1.4
89	A1g	1416	1416	1416	1416	9.100e+37 0.2	4.340e+37 0.1	1.344e+38 0.3
90	B2g	1446	1446	1446	1446	1.688e+38 0.4	2.320e+38 0.5	4.008e+38 0.8
91	B2u	1452	1452	1489	1452
92	Au	1489	1489	1490	1489
93	B1g	1490	1490	1493	1490	8.665e+38 1.8	1.191e+39 2.5	2.058e+39 4.3
94	B3g	1493	1493	1514	1493	9.791e+36 0.0	1.346e+37 0.0	2.325e+37 0.0
95	B3u	1514	1543	1533	1514
96	B1u	1543	1582	1543	1554

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥