Table 12.

DFTB2 and DFTB3 Errors for the Bond Lengths of 35 Phosphorous Containing Molecules^a in Comparison to B3LYP/6-31+G(d,p)

bond typeb	n c	DFTB2			DFTB3/calc			DFTB3/fit d
		MAX	MSE	MUE	MAX	MSE	MUE	MAX	MSE	MUE
rC-P	6	0.042	+0.022	0.022	0.041	+0.018	0.018	0.041	+0.021	0.021
rC=P	1	0.056	+0.056	0.056	0.049	+0.049	0.049	-	-	-
rH-P	9	0.061	+0.024	0.024	0.047	+0.020	0.021	0.044	+0.018	0.019
rN-P	1	0.001	+0.001	0.001	0.001	+0.001	0.001	0.001	+0.001	0.001
rO-P	43	0.404	+0.001	0.029	0.150	−0.022	0.026	0.200	−0.029	0.031
rO=P	33	0.029	+0.007	0.011	0.027	+0.008	0.011	0.017	+0.003	0.006
rP-P	4	0.109	+0.077	0.077	0.118	+0.081	0.081	0.148	+0.098	0.098
rP#P	1	0.003	+0.003	0.003	0.003	+0.003	0.003	0.003	+0.003	0.003
rP-S	5	0.164	+0.121	0.121	0.137	+0.103	0.103	0.128	+0.098	0.098
rP=S	3	0.070	+0.062	0.062	0.064	+0.059	0.059	0.061	+0.059	0.059
rOHhb	3	0.141	−0.138	0.138	0.225	−0.222	0.222	0.192	−0.186	0.186
overall e	196	0.404	+0.010	0.022	0.225	+0.002	0.021	0.200	−0.000	0.021

^aGeometries for all molecules are listed in Supporting Information.

^bbond situations between two atom types, “-” means a single bond, “=” a double bond, rP#P is the bond length of the molecule P₂, and rOHhb are hydrogen bonds between a phosphate group and a water, all specifications can be found in Supporting Information

^cnumber of comparisons

^dtrimethylmethylenephosphorane does not converge and is excluded from the statistics

^eAlso the bond types rCC, rCH, rCO, rC=O, rHO, rCS, and rHS are included in the overall performance.