Table 3. Structural formulae [for O₂₀(OH⁻)₄] and parameters of the natural and homoionic samples obtained from the mean chemical compositions.

So is the number of octahedral cations, St the number of tetrahedral cations, CT the tetrahedral charge, CO the octahedral charge and CI the interlayer charge.

	Si	AlIV	Fe3+	AlVI	Fe3+	Mg	Ca	Na	K	So	St	CT	CO	CT+CO	CI	Classification
CAR1	7.74	0.26		2.86	0.34	1.12	0.13	0.06	0.07	4.32	8.00	−0.26	−0.16	−0.42	0.39	Low-charge beidellite
CAR1 Ca	7.80	0.20		2.82	0.28	1.01	0.38	0.05	0.04	4.11	8.00	−0.20	−0.68	−0.88	0.85	Montmorillonite
CAR2	8.01			2.78	0.47	0.97	0.11		0.08	4.22	8.01	0.00	−0.31	−0.30	0.30	Low-charge montmorillonite
CAR2 Ca	7.96	0.04		3.01	0.22	0.81	0.37		0.01	4.04	8.00	−0.04	−0.69	−0.73	0.75	Montmorillonite
LTBB	7.69	0.31		3.23	0.21	0.85	0.15	0.02	0.01	4.29	8.00	−0.31	0.02	−0.29	0.33	Low-charge beidellite
LTBB Ca	7.74	0.26		3.21	0.17	0.77	0.29			4.15	8.00	−0.26	−0.32	−0.58	0.58	Montmorillonite
WYO	7.86	0.14		3.13	0.39	0.51	0.08	0.26	0.11	4.03	8.00	−0.14	−0.42	−0.56	0.53	Montmorillonite
WYO Ca	7.87	0.13		3.15	0.40	0.45	0.29			4.00	8.00	−0.13	−0.45	−0.58	0.58	Montmorillonite
ESB6	7.40	0.60		1.16	0.34	3.75	0.14	0.02	0.28	5.25	8.00	−0.60	0.00	−0.60	0.58	Saponite
ESB6 Ca	7.42	0.58		1.55	0.44	2.94	0.27		0.18	4.93	8.00	−0.58	−0.15	−0.73	0.72	Saponite
RESQ	7.98	0.02		0.12	0.02	5.76	0.02		0.01	5.90	8.00	−0.02	−0.06	−0.08	0.05	Kerolite
RESQ Ca	7.92	0.08		0.13	0.04	5.60	0.19		0.01	5.77	8.00	−0.08	−0.29	−0.37	0.39	Low-charge stevensite
ROS	7.92	0.08		0.14	0.05	5.66	0.06	0.07	0.02	5.85	8.00	−0.08	−0.11	−0.19	0.21	Kerolite
ROS Ca	7.81	0.17	0.02		0.07	5.80	0.19			5.87	8.00	−0.19	−0.19	−0.38	0.38	Low-charge saponite–stevensite