Structure and Electronic Properties of Transition Metal Doped Kaolinite Nanoclay

Table 1 Calculated and experimental unit cell parameters (Å) and averaged bond lengths (Å) of kaolinite and the most stable TM–kaolinite structure with AFM, FM, and NM states. The M–O bond represents the Al–O bond for kaolinite or the TM–O bond for TM–kaolinite. The average charge and spin of M atoms are also given

	Kaolinite			Cr–kaolinite		Mn–kaolinite		Fe–kaolinite		Co–kaolinite
	NM			AFM	FM	AFM	FM	AFM	FM	NM
	PBE	PBE-D2	Exp [45]	PBE-D2
V (Å³)	340.99	328.47	329.91	338.22	339.59	349.70	354.59	347.71	348.32	323.96
a (Å)	5.209	5.177	5.154	5.224	5.238	5.242	5.319	5.291	5.282	5.126
b (Å)	9.042	8.981	8.942	9.068	9.092	9.234	9.249	9.183	9.173	8.894
c (Å)	7.483	7.308	7.401	7.374	7.368	7.41	7.44	7.407	7.437	7.314
α (deg)	91.78	91.69	91.69	90.89	90.89	88.28	91.17	91.6	91.46	90.44
β (deg)	104.30	104.69	104.61	104.45	104.55	102.64	104.31	104.87	104.76	103.73
γ (deg)	89.81	89.82	89.82	89.87	89.84	88.76	89.77	89.92	89.88	89.83
Si–O_b	1.634	1.630	1.620	1.637	1.639	1.650	1.655	1.651	1.648	1.627
Si–O_a	1.610	1.605	1.610	1.601	1.604	1.596	1.602	1.600	1.602	1.610
M–O	2.004	2.000	1.971	2.061	2.058	2.214	2.117	2.100	2.098	1.999
M–OH_inner	1.937	1.941	1.921	2.020	2.014	2.050	2.038	2.042	2.048	1.956
M–OH_inter	1.867	1.859	1.857	1.943	1.948	1.962	1.977	1.954	1.969	1.922
O–H	0.974	0.977		0.983	0.983	0.987	0.986	0.985	0.984	0.987
Charge	1.84	1.84		1.25	1.26	1.21	1.24	1.37	1.37	1.08
Spin	0.00	0.00		3.06	3.08	3.80	3.84	4.02	4.06	0.00