III.G.1.a.

Comparison of levels of theory for Mg-Cl

Click on an entry for a histogram of the values.
The subscript refers to how many bonds of that type have been calculated.

average calculated bond lengths (Å)

Methods with predefined basis sets
semi-empirical	AM1	3.6453 2
	PM3	1.9700 5
	PM6	2.2118 5
composite	G2	2.2378 5
	G3	2.2378 5
	G3B3	2.2403 5
	CBS-Q	2.2683 3

average calculated bond lengths (Å)

Methods with standard basis sets
		STO-3G	3-21G	3-21G*	6-31G	6-31G*	6-31G**	6-31+G**	6-311G*	6-311G**	6-31G(2df,p)	6-311+G(3df,2p)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z
hartree fock	HF	2.2420 5	2.3015 5	2.2390 5	2.3078 5	2.1865 4	2.2378 5	2.2356 5	2.2367 5	2.2366 5	2.2176 5	2.1873 3	2.2612 5	2.2353 5	2.2157 4	2.2134 5	2.2817 2	2.2146 5	2.2356 3	2.2151 5
hartree fock	ROHF		2.3024 1	2.2382 1		2.2342 1	2.2342 1	2.2373 1	2.2344 1
density functional	LSDA	2.1891 5	2.2467 5	2.2141 5	2.2756 5	2.2135 5	2.2135 5	2.2167 5	2.2160 5	2.2160 5	2.1932 5			2.2132 5	2.1940 5	2.2253 2	2.2217 5	2.2291 2	2.2242 2
	SVWN		2.2723 5			2.1702 4		2.2169 5
	BLYP	2.2360 5	2.3072 5	2.2512 5	2.3188 5	2.2570 5	2.2570 5	2.2618 5	2.2645 5	2.2647 5	2.2690 3			2.2532 4	2.2406 4		2.2312 3
	B1B95	2.2210 5	2.2642 5	2.2318 5	2.2949 5	2.2301 5	2.2311 5	2.2676 3	2.2608 4	2.2608 4	2.2122 5			2.2303 5	2.2111 5	2.2479 2	2.2368 4	2.2506 2	2.3865 1
	B3LYP	2.2259 5	2.2948 5	2.2370 5	2.3038 5	2.2403 5	2.2403 5	2.2437 5	2.2456 5	2.3031 2	2.2212 5	2.2211 1	2.2588 5	2.2376 5	2.2227 4	2.2491 3	2.2948 2	2.2238 5	2.2482 3	2.2221 5
	B3LYPultrafine					2.2403 5
	B3PW91	2.3693 2	2.2966 5	2.2378 5	2.3005 5	2.2354 5	2.2354 5	2.2372 5	2.2369 5	2.2888 2	2.2440 3			2.2345 4	2.2158 4		2.2120 3
	mPW1PW91	2.3648 2	2.2930 5	2.2338 4	2.2966 5	2.2312 5	2.2312 5	2.2327 5	2.2318 5	2.2320 5	2.2391 3			2.2305 4	2.2111 4		2.2387 1
	M06-2X					2.2255 5
	PBEPBE	2.3643 2	2.3016 5	2.2446 4	2.3077 4	2.2451 5	2.2451 5	2.2483 5	2.2485 5	2.2485 5	2.2252 5	2.2251 1		2.2437 5	2.2262 5	2.2640 2		2.1864 2	2.2627 2
	PBEPBEultrafine					2.2148 3
	HSEh1PBE					2.2316 5
Moller Plesset perturbation	MP2FC	2.4475 2	2.3116 5	2.2226 5	2.3214 5	2.2213 5	2.2213 5	2.2218 5	2.2235 5	2.2236 5	2.2171 5		2.2579 5	2.2306 5	2.2505 2	2.2384 3	2.2816 3	2.2450 3	2.2397 3	2.2166 5
	MP2FU	2.4450 2	2.3122 5	2.2203 4	2.3224 4	2.2188 5	2.2188 5	2.2197 5	2.2225 5	2.2661 2	2.2437 2			2.2656 2	2.2339 2	2.2172 3	2.2249 3		2.2239 2	2.1994 5
	MP3					2.2198 5
	MP4		2.3163 4			2.2235 5			2.2252 1	2.2684 2					2.2174 1
	B2PLYP					2.2300 5		2.2324 5
Configuration interaction	CID		2.3670 2	2.2621 2	2.3870 2	2.2226 5			2.2530 3
Configuration interaction	CISD		2.3690 2	2.2634 2	2.3886 2	2.2235 5			2.2694 2
Quadratic configuration interaction	QCISD		2.3174 5	2.2250 4	2.3298 4	2.2241 5	2.2246 4	2.2248 5	2.2249 5	2.2544 3	2.2543 2			2.2328 5	2.2396 3
Quadratic configuration interaction	QCISD(T)					2.2245 5			2.2266 1					2.2699 2	2.2512 2		2.2995 2	2.2576 2
Coupled Cluster	CCD		2.3149 4	2.2229 4	2.3266 4	2.2221 5	2.2228 4	2.2221 4	2.2233 5	2.2677 2	2.2534 2			2.2311 5	2.2511 2		2.2963 2	2.2551 2
	CCSD					2.2235 5			2.2244 1
	CCSD(T)					2.1993 3	2.2229 1		2.2262 1		2.1804 2	2.2206 1		2.2573 3	2.2397 3		2.2855 3	2.2463 3
	CCSD(T)=FULL					2.2590 2

average calculated bond lengths (Å)

Methods with effective core potentials (select basis sets)
		CEP-31G	CEP-31G*	CEP-121G	CEP-121G*	LANL2DZ	SDD
hartree fock	HF	2.3271 5	2.2348 5	2.3178 5	2.2330 5	2.2717 5	2.3284 5
density functional	B1B95	2.2730 2	2.2166 3
density functional	B3LYP	2.3305 5	2.2466 5	2.3239 5	2.2458 5	2.2774 5	2.3280 5
Moller Plesset perturbation	MP2FC	2.3430 5	2.2369 5	2.3354 5	2.2286 5	2.2796 5	2.3445 5

For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.