- NESQUEHONITE - MgCO₃3H₂O

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:	56		Pccn
Lattice parameters (Å):	7.7010	5.3650		12.1260
Angles (°):	90	92.14		90

Symmetry (theoretical):

Space group:	56		Pccn
Lattice parameters (Å):	7.3582	5.2820		11.4781
Angles (°):	90	91.56		90

Cell contents:

Number of atoms:	56
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Mg:	0.2618	0.0774	0.1471
C:	0.2295	0.1251	0.4162
O:	0.5375	0.0863	0.1687
O:	0.9908	0.0673	0.1384
O:	0.2744	0.3970	0.0503
O:	0.2349	0.1897	0.3099
O:	0.2735	0.8098	0.0103
O:	0.3042	0.3431	0.8279
H:	0.5988	0.1660	0.1011
H:	0.5960	0.9096	0.1717
H:	0.9002	0.1271	0.0781
H:	0.9323	0.0786	0.2150
H:	0.1840	0.3387	0.7844
H:	0.2852	0.3766	0.9138
Mg:	0.2382	0.5774	0.3529
C:	0.2705	0.6251	0.0838
O:	0.9625	0.5863	0.3313
O:	0.5092	0.5673	0.3616
O:	0.2256	0.8970	0.4497
O:	0.2651	0.6897	0.1901
O:	0.2265	0.3098	0.4897
O:	0.1958	0.8431	0.6721
H:	0.9012	0.6660	0.3989
H:	0.9040	0.4096	0.3283
H:	0.5998	0.6271	0.4219
H:	0.5677	0.5786	0.2850
H:	0.3160	0.8387	0.7156
H:	0.2148	0.8766	0.5862
Mg:	0.7382	0.9226	0.8529
C:	0.7705	0.8749	0.5838
O:	0.4625	0.9137	0.8313
O:	0.0092	0.9327	0.8616
O:	0.7256	0.6030	0.9497
O:	0.7651	0.8103	0.6901
O:	0.7265	0.1902	0.9897
O:	0.6958	0.6569	0.1721
H:	0.4012	0.8340	0.8989
H:	0.4040	0.0904	0.8283
H:	0.0998	0.8729	0.9219
H:	0.0677	0.9214	0.7850
H:	0.8160	0.6613	0.2156
H:	0.7148	0.6234	0.0862
Mg:	0.7618	0.4226	0.6471
C:	0.7295	0.3749	0.9162
O:	0.0375	0.4137	0.6687
O:	0.4908	0.4327	0.6384
O:	0.7744	0.1030	0.5503
O:	0.7349	0.3103	0.8099
O:	0.7735	0.6902	0.5103
O:	0.8042	0.1569	0.3279
H:	0.0988	0.3340	0.6011
H:	0.0960	0.5904	0.6717
H:	0.4002	0.3729	0.5781
H:	0.4323	0.4214	0.7150
H:	0.6840	0.1613	0.2844
H:	0.7852	0.1234	0.4138

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	Ag	70	70	70	70	6.613e+38 0.6	3.183e+38 0.3	9.797e+38 0.9
5	Au	85	85	86	85
6	Bg	86	86	88	86	3.450e+38 0.3	5.037e+38 0.5	8.487e+38 0.8
7	Bu	95	96	95	95
8	Ag	98	98	98	98	3.909e+38 0.4	5.311e+37 0.0	4.440e+38 0.4
9	Au	103	103	103	103
10	Bg	107	107	107	107	6.243e+38 0.6	1.006e+39 0.9	1.631e+39 1.5
11	Ag	114	114	114	114	7.425e+38 0.7	7.400e+38 0.7	1.483e+39 1.4
12	Ag	119	119	119	119	9.533e+38 0.9	1.502e+38 0.1	1.104e+39 1.0
13	Bu	119	120	119	120
14	Bg	121	121	121	121	2.971e+37 0.0	3.298e+37 0.0	6.270e+37 0.1
15	Bg	138	138	138	138	4.301e+38 0.4	6.858e+38 0.6	1.116e+39 1.0
16	Au	140	140	142	140
17	Bg	147	147	147	147	3.137e+38 0.3	3.624e+38 0.3	6.761e+38 0.6
18	Au	166	166	166	166
19	Bu	166	166	166	167
20	Ag	172	172	172	172	9.528e+38 0.9	1.274e+38 0.1	1.080e+39 1.0
21	Bg	176	176	176	176	5.630e+37 0.1	6.327e+37 0.1	1.196e+38 0.1
22	Au	180	180	180	180
23	Ag	183	183	183	183	4.072e+38 0.4	1.559e+38 0.1	5.631e+38 0.5
24	Bu	189	192	189	190
25	Bg	192	193	192	192	9.746e+38 0.9	1.404e+39 1.3	2.378e+39 2.2
26	Bu	196	197	196	196
27	Au	197	198	198	197
28	Ag	198	202	200	198	4.488e+39 4.1	4.210e+39 3.9	8.698e+39 8.0
29	Bg	207	207	207	207	6.628e+38 0.6	8.065e+38 0.7	1.469e+39 1.4
30	Ag	208	208	208	208	1.599e+39 1.5	2.038e+38 0.2	1.803e+39 1.7
31	Au	219	219	220	219
32	Ag	221	221	221	221	4.286e+39 4.0	5.656e+39 5.2	9.942e+39 9.2
33	Bu	233	233	233	233
34	Bg	237	237	237	237	1.453e+39 1.3	1.033e+39 1.0	2.486e+39 2.3
35	Ag	237	237	237	237	3.262e+39 3.0	4.216e+39 3.9	7.478e+39 6.9
36	Au	239	239	243	239
37	Bu	243	243	244	243
38	Au	253	253	253	253
39	Bu	265	265	265	265
40	Bg	265	267	265	270	7.246e+37 0.1	9.218e+37 0.1	1.646e+38 0.2
41	Ag	270	270	270	271	7.212e+38 0.7	8.489e+38 0.8	1.570e+39 1.5
42	Au	271	271	271	273
43	Bu	282	284	282	285
44	Bg	285	285	285	285	1.337e+38 0.1	2.102e+38 0.2	3.439e+38 0.3
45	Bg	294	294	294	294	2.572e+38 0.2	2.934e+38 0.3	5.506e+38 0.5
46	Bu	295	296	295	296
47	Au	296	300	298	296
48	Ag	300	310	300	300	1.561e+39 1.4	1.653e+39 1.5	3.214e+39 3.0
49	Bg	310	317	310	310	1.102e+39 1.0	1.842e+39 1.7	2.944e+39 2.7
50	Bu	327	330	327	330
51	Au	330	330	330	330
52	Ag	330	330	331	334	7.280e+38 0.7	5.111e+38 0.5	1.239e+39 1.1
53	Ag	336	336	336	336	3.893e+38 0.4	4.430e+38 0.4	8.322e+38 0.8
54	Bu	343	354	343	343
55	Au	354	354	354	354
56	Bg	354	359	358	354	1.730e+38 0.2	2.210e+38 0.2	3.941e+38 0.4
57	Au	362	362	369	362
58	Ag	369	369	370	369	1.521e+39 1.4	9.572e+37 0.1	1.617e+39 1.5
59	Bu	377	382	377	380
60	Bg	382	383	382	382	1.562e+38 0.1	2.446e+38 0.2	4.008e+38 0.4
61	Bu	391	391	391	399
62	Ag	399	399	399	402	6.144e+38 0.6	2.519e+38 0.2	8.663e+38 0.8
63	Au	402	402	408	408
64	Bg	408	408	417	409	2.617e+38 0.2	4.135e+38 0.4	6.752e+38 0.6
65	Au	417	417	418	417
66	Bg	418	418	424	418	7.570e+37 0.1	1.204e+38 0.1	1.961e+38 0.2
67	Ag	424	424	425	424	1.987e+39 1.8	1.042e+39 1.0	3.029e+39 2.8
68	Bu	425	426	434	453
69	Au	490	490	496	490
70	Ag	498	498	498	498	3.232e+38 0.3	2.472e+38 0.2	5.704e+38 0.5
71	Bu	514	526	514	515
72	Bg	526	530	526	526	2.145e+38 0.2	2.478e+38 0.2	4.623e+38 0.4
73	Bu	648	648	648	648
74	Bg	650	650	650	650	1.971e+38 0.2	3.267e+38 0.3	5.238e+38 0.5
75	Au	652	652	657	652
76	Ag	675	675	675	675	1.463e+39 1.4	1.587e+39 1.5	3.051e+39 2.8
77	Bu	682	684	682	684
78	Bu	686	686	686	686
79	Bg	687	687	687	687	1.027e+39 0.9	1.698e+39 1.6	2.724e+39 2.5
80	Au	691	691	692	691
81	Ag	700	700	700	700	9.418e+38 0.9	1.001e+39 0.9	1.943e+39 1.8
82	Bg	711	711	711	711	5.205e+38 0.5	5.536e+38 0.5	1.074e+39 1.0
83	Ag	725	725	725	725	1.049e+39 1.0	1.406e+39 1.3	2.455e+39 2.3
84	Bu	726	726	726	731
85	Au	734	734	734	734
86	Au	741	741	742	741
87	Bg	742	742	745	742	4.738e+38 0.4	6.514e+38 0.6	1.125e+39 1.0
88	Ag	745	745	757	745	4.602e+38 0.4	4.963e+38 0.5	9.566e+38 0.9
89	Ag	757	757	759	757	9.074e+38 0.8	8.836e+38 0.8	1.791e+39 1.7
90	Bu	759	759	760	762
91	Au	763	763	764	763
92	Bg	764	764	765	764	4.827e+37 0.0	7.700e+37 0.1	1.253e+38 0.1
93	Bg	765	765	783	765	1.037e+38 0.1	1.207e+38 0.1	2.244e+38 0.2
94	Bu	783	783	789	784
95	Au	794	794	795	794
96	Ag	799	799	799	799	3.228e+38 0.3	2.426e+38 0.2	5.653e+38 0.5
97	Au	821	821	822	821
98	Ag	822	822	822	822	3.981e+38 0.4	2.006e+38 0.2	5.987e+38 0.6
99	Bu	834	849	834	838
100	Bg	851	851	851	851	1.308e+38 0.1	1.401e+38 0.1	2.709e+38 0.3
101	Au	865	865	866	865
102	Ag	872	872	872	872	2.638e+38 0.2	1.861e+38 0.2	4.499e+38 0.4
103	Bu	878	879	878	879
104	Bg	879	879	879	879	6.214e+38 0.6	9.634e+38 0.9	1.585e+39 1.5
105	Ag	899	899	899	899	2.288e+39 2.1	1.478e+39 1.4	3.766e+39 3.5
106	Bu	900	900	900	900
107	Au	900	900	905	919
108	Bg	919	919	919	921	1.646e+37 0.0	1.761e+37 0.0	3.407e+37 0.0
109	Au	943	943	947	943
110	Ag	953	953	953	953	7.645e+38 0.7	3.004e+38 0.3	1.065e+39 1.0
111	Bu	957	960	957	960
112	Bg	960	960	960	960	3.106e+38 0.3	4.349e+38 0.4	7.455e+38 0.7
113	Au	1001	1001	1003	1001
114	Bu	1006	1008	1006	1008
115	Ag	1008	1009	1008	1008	3.408e+39 3.2	2.365e+38 0.2	3.645e+39 3.4
116	Bg	1023	1023	1023	1023	5.400e+37 0.0	7.065e+37 0.1	1.246e+38 0.1
117	Ag	1117	1117	1117	1117	1.560e+39 1.4	5.360e+37 0.0	1.613e+39 1.5
118	Ag	1118	1118	1118	1118	4.068e+40 37.6	1.399e+39 1.3	4.208e+40 38.9
119	Bu	1118	1118	1118	1119
120	Bg	1119	1119	1119	1119	9.705e+37 0.1	1.117e+38 0.1	2.087e+38 0.2
121	Au	1181	1181	1181	1181
122	Ag	1189	1189	1189	1189	1.018e+39 0.9	3.946e+38 0.4	1.413e+39 1.3
123	Bu	1256	1259	1256	1256
124	Bg	1259	1262	1259	1259	3.635e+37 0.0	5.151e+37 0.0	8.786e+37 0.1
125	Bu	1422	1422	1422	1430
126	Bg	1430	1430	1430	1435	1.003e+39 0.9	1.541e+39 1.4	2.544e+39 2.4
127	Ag	1435	1435	1435	1462	3.519e+38 0.3	2.979e+38 0.3	6.498e+38 0.6
128	Au	1465	1465	1523	1465
129	Bu	1539	1539	1539	1547
130	Ag	1547	1547	1547	1551	1.845e+39 1.7	1.844e+38 0.2	2.029e+39 1.9
131	Bg	1551	1551	1551	1551	6.057e+37 0.1	7.972e+37 0.1	1.403e+38 0.1
132	Bu	1558	1560	1558	1560
133	Au	1560	1567	1561	1567
134	Bg	1567	1567	1567	1573	4.316e+38 0.4	4.676e+38 0.4	8.992e+38 0.8
135	Ag	1573	1573	1573	1579	3.232e+38 0.3	3.949e+38 0.4	7.180e+38 0.7
136	Au	1579	1579	1604	1589
137	Au	1616	1616	1624	1616
138	Ag	1624	1624	1628	1624	8.249e+38 0.8	3.561e+38 0.3	1.181e+39 1.1
139	Bu	1634	1637	1634	1637
140	Bg	1637	1645	1637	1638	3.163e+37 0.0	4.177e+37 0.0	7.340e+37 0.1
141	Bu	1661	1662	1661	1663
142	Bg	1663	1663	1663	1663	1.718e+38 0.2	1.853e+38 0.2	3.571e+38 0.3
143	Ag	1669	1669	1669	1669	1.793e+39 1.7	5.477e+38 0.5	2.341e+39 2.2
144	Au	1672	1672	1674	1672
145	Ag	2583	2583	2583	2583	8.543e+40 79.0	5.490e+39 5.1	9.092e+40 84.0
146	Au	2591	2591	2628	2591
147	Bg	2628	2628	2635	2628	9.450e+39 8.7	1.495e+40 13.8	2.440e+40 22.6
148	Bu	2635	2643	2677	2636
149	Bu	2835	2835	2835	2839
150	Ag	2839	2839	2839	2861	4.372e+40 40.4	2.354e+40 21.8	6.726e+40 62.2
151	Au	2861	2861	2863	2863
152	Bg	2863	2863	2863	2898	3.772e+39 3.5	4.312e+39 4.0	8.084e+39 7.5
153	Ag	2996	2996	2996	2996	9.175e+40 84.8	1.643e+40 15.2	1.082e+41 100.0
154	Bu	3003	3004	3003	3004
155	Bg	3004	3005	3004	3009	2.648e+39 2.4	3.989e+39 3.7	6.637e+39 6.1
156	Au	3009	3009	3011	3026
157	Au	3124	3124	3126	3124
158	Ag	3126	3126	3126	3126	3.654e+40 33.8	1.386e+40 12.8	5.040e+40 46.6
159	Bu	3137	3138	3137	3138
160	Bg	3138	3168	3138	3138	3.998e+39 3.7	5.267e+39 4.9	9.265e+39 8.6
161	Ag	3168	3172	3168	3168	8.387e+40 77.5	1.050e+40 9.7	9.438e+40 87.2
162	Bg	3173	3173	3173	3173	3.614e+39 3.3	3.859e+39 3.6	7.473e+39 6.9
163	Bu	3187	3219	3187	3219
164	Au	3221	3221	3221	3221
165	Ag	3223	3223	3223	3223	1.427e+40 13.2	1.736e+40 16.1	3.164e+40 29.2
166	Bu	3227	3232	3227	3257
167	Bg	3257	3257	3257	3258	2.550e+38 0.2	3.760e+38 0.3	6.310e+38 0.6
168	Au	3258	3258	3265	3292

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥