Table 5.

Average unsigned errors in calculated heats of formation (kcal mol⁻¹)

Element	PM6	No.	PM5	No.	PM3	No.	AM1	No.
Hydrogen	7.29	3039	13.89	2340	17.09	2340	21.12	2270
Helium	0.00	1	0.00	1	0.00	1	0.00	1
Lithium	7.98	83	15.31	83	18.02	83	18.84	82
Beryllium	5.92	34	29.06	34	29.58	34	18.51	34
Boron	6.44	122	10.81	120	11.84	120	–	–
Carbon	7.31	2828	13.03	2155	15.06	2155	19.42	2123
Nitrogen	8.22	1067	16.45	761	20.96	761	24.23	744
Oxygen	8.42	1758	16.59	1243	20.13	1244	27.68	1229
Fluorine	8.49	497	22.31	350	21.25	350	37.40	334
Neon	0.00	1	0.00	1	0.00	1	0.00	1
Sodium	5.72	40	8.57	39	9.47	39	10.77	38
Magnesium	9.84	66	12.07	66	17.94	66	18.71	66
Aluminum	7.61	75	17.49	75	19.15	75	18.99	75
Silicon	6.51	98	9.28	96	12.80	96	17.00	95
Phosphorus	8.20	110	16.01	98	17.36	98	20.06	95
Sulfur	8.81	427	15.40	330	18.44	330	26.38	323
Chlorine	8.28	670	16.69	390	18.71	390	23.06	383
Argon	0.00	1	0.00	1	0.00	1	0.00	1
Potassium	6.53	43	12.33	42	9.36	42	28.38	41
Calcium	11.87	43	28.68	43	43.44	43	63.20	43
Scandium	10.33	52	–	–	–	–	–	–
Titanium	10.20	85	–	–	–	–	–	–
Vanadium	14.29	59	–	–	–	–	–	–
Chromium	14.09	60	–	–	–	–	–	–
Manganese	12.77	44	–	–	–	–	–	–
Iron	18.31	76	–	–	–	–	–	–
Cobalt	15.51	42	–	–	–	–	–	–
Nickel	15.10	51	–	–	–	–	–	–
Copper	13.00	47	–	–	–	–	–	–
Zinc	5.56	54	17.84	54	32.93	54	37.06	54
Gallium	7.51	47	29.12	47	37.58	47	46.87	47
Germanium	9.83	67	12.20	67	15.86	67	19.12	67
Arsenic	6.94	49	15.22	49	16.68	49	17.34	49
Selenium	4.40	25	39.58	25	39.71	25	32.00	25
Bromine	7.37	330	17.20	199	25.04	199	28.22	199
Krypton	0.00	1	0.00	1	0.00	1	0.00	1
Rubidium	10.91	24	16.57	24	21.47	24	29.33	23
Strontium	7.72	38	52.46	38	103.16	38	57.21	38
Yttrium	13.28	51	–	–	–	–	–	–
Zirconium	11.18	46	–	–	–	–	–	–
Niobium	8.57	51	–	–	–	–	–	–
Molybdenum	13.41	70	–	–	–	–	35.77	69
Technetium	15.14	50	–	–	–	–	–	–
Ruthenium	13.87	56	–	–	–	–	–	–
Rhodium	20.92	32	–	–	–	–	–	–
Palladium	11.65	47	–	–	–	–	–	–
Silver	4.67	14	–	–	–	–	–	–
Cadmium	3.49	38	34.66	38	61.92	38	–	–
Indium	7.33	54	31.53	54	29.83	54	32.16	54
Tin	7.14	77	16.83	77	17.10	77	20.21	77
Antimony	5.41	58	30.98	58	34.61	58	35.00	58
Tellurium	8.20	45	35.66	45	46.80	45	22.91	45
Iodine	7.23	279	23.77	176	25.90	176	36.55	175
Xenon	0.00	1	0.00	1	0.00	1	0.00	1
Cesium	6.89	40	37.01	40	35.22	40	55.33	39
Barium	12.12	37	98.20	37	154.65	37	161.09	37
Lanthanum	10.37	37	–	–	–	–	–	–
Lutetium	7.68	24	–	–	–	–	–	–
Hafnium	8.52	37	–	–	–	–	–	–
Tantalum	14.37	36	–	–	–	–	–	–
Tungsten	7.38	28	–	–	–	–	–	–
Rhenium	10.40	57	–	–	–	–	–	–
Osmium	6.46	19	–	–	–	–	–	–
Iridium	10.21	25	–	–	–	–	–	–
Platinum	11.61	77	–	–	–	–	–	–
Gold	12.82	32	–	–	–	–	–	–
Mercury	5.94	51	16.39	51	17.67	51	19.75	51
Thallium	10.42	44	32.63	44	73.96	45	73.18	45
Lead	7.92	44	18.08	44	14.18	44	16.71	44
Bismuth	7.74	53	99.88	53	28.95	53	119.23	53