Bond lengths in angstrom (Å) for CH₃NH₃MX₃ structures using the GGA-PBE level of theory.

Material	Bond length (Å)
	Equatorial plane									Axial plane
	M–X1	M–X2	M–X3	M–X4	N–C	N–H1	N–H2	C–H1	C–H2	M–X5	M–X6	N–H3	C–H3
CH3NH3CuCl3	2.33	2.33	2.45	2.41	1.49	1.05	1.05	1.09	1.09	2.39	2.42	1.05	1.09
CH3NH3ZnCl3	2.22	2.22	2.30	2.30	1.49	1.05	1.04	1.09	1.09	2.40	2.40	1.05	1.10
CH3NH3GaCl3	2.37	2.37	2.36	2.36	1.46	1.06	1.05	1.10	1.10	2.51	2.50	1.05	1.10
CH3NH3GeCl3	2.33	2.33	4.43	2.37	1.51	1.04	1.04	1.10	1.09	2.70	2.83	1.04	1.09
CH3NH3SnCl3	2.83	2.83	2.98	2.98	1.49	1.05	1.04	1.09	1.09	2.93	2.91	1.04	1.09
CH3NH3PbCl3	2.91	2.83	2.83	2.90	1.49	1.05	1.05	1.09	1.09	2.93	2.91	1.05	1.09
CH3NH3CuBr3	2.32	4.16	4.16	2.32	1.49	1.05	1.05	1.09	1.09	2.58	2.58	1.05	1.09
CH3NH3ZnBr3	2.32	4.30	4.30	2.32	1.49	1.06	1.04	1.09	1.09	2.94	2.94	1.04	1.09
CH3NH3GaBr3	2.75	2.97	2.75	2.75	1.49	1.05	1.04	1.09	1.09	2.85	2.85	1.04	1.09
CH3NH3GeBr3	2.86	2.98	2.98	2.86	1.50	1.04	1.04	1.09	1.09	2.88	2.88	1.04	1.09
CH3NH3SnBr3	3.03	3.04	3.04	3.03	1.50	1.05	1.04	1.10	1.09	3.10	3.10	1.04	1.09
CH3NH3PbBr3	3.29	3.29	3.29	3.29	1.51	1.04	1.04	1.09	1.09	3.12	3.12	1.04	1.09
CH3NH3CuI3	2.54	3.83	3.83	2.54	1.49	1.05	1.04	1.09	1.09	2.81	2.81	1.04	1.09
CH3NH3ZnI3	2.56	3.95	3.95	2.56	1.49	1.06	1.04	1.09	1.10	3.11	3.11	1.04	1.10
CH3NH3GaI3	3.09	3.12	3.12	3.09	1.49	1.05	1.04	1.09	1.09	3.01	3.01	1.04	1.09
CH3NH3GeI3	3.16	3.18	3.18	3.16	1.50	1.04	1.04	1.09	1.09	3.11	3.11	1.04	1.09
CH3NH3SnI3	3.06	3.08	3.08	3.06	1.50	1.05	1.03	1.09	1.09	3.06	3.06	1.03	1.09
CH3NH3PbI3	3.30	3.34	3.34	3.30	1.50	1.05	1.04	1.09	1.09	3.29	3.29	1.04	1.09