Table 4. Thermochemical Benson Group Pair Contributions for Standard Enthalpies of Formation (Δ_fH_298K^°, kJ mol^–1), Entropies (S_298K, J K^–1 mol^–1), and Heat Capacities (C_p, J K^–1 mol^–1) Derived from the Results of W1X-1 Calculations.

Benson group	ΔfH° 298 K	S° 298 K	Cp 298 K	Cp 500 K	Cp 1000 K
Si–(CB)(H)3 + CB–(CB)2(Si)	56	104	35	58	83
Si–(C)(CB)(H)2 + CB–(CB)2(Si)	36	37	39	57	74
Si–(CB)(H)2(O) + CB–(CB)2(Si)	50	31	44	62	80
Si–(CB)2(H)2 + CB–(CB)2(Si)	72	–3	49	74	98
Si–(C)2(CB)(H) + CB–(CB)2(Si)	13	–47	41	53	62
Si–(CB)(CD)2(H) + CB–(CB)2(Si)	41	–65	36	53	63
Si–(CB)(H)(O)2 + CB–(CB)2(Si)	14	–63	41	53	62
Si–(C)(CB)(CD)(H) + CB–(CB)2(Si)	26	–60	37	52	62
Si–(C)(CB)(H)(O) + CB–(CB)2(Si)	18	–53	40	53	62
Si–(C)3(CB) + CB–(CB)2(Si)	–11	–118	44	50	50
Si–(C)2(CB)2 + CB–(CB)2(Si)	22	–167	55	68	73
Si–(CB)2(O)2 + CB–(CB)2(Si)	14	–182	52	66	73
Si–(C)2(CB)(CD) + CB–(CB)2(Si)	2	–135	40	49	50
Si–(C)(CB)(CD)2 + CB–(CB)2(Si)	14	–147	38	50	51
Si–(C)(CB)(O)2 + CB–(CB)2(Si)	–19	–143	45	52	53
Si–(CB)(CD)(O)2 + CB–(CB)2(Si)	–4	–154	55	70	74
2 Si–(C)3(N) + N–(H)(Si)	–218	–134	93	98	96