Mean Bond Enthalpies (ΔH_b^o, kJ/mol)^a

single	H	C	O	N	F	Cl	Br	I	S	Si
H	436	413	463	391	563	432	366	299	339	325
C		348	351	292	441	328	276	240	259	290
O			139	175	185	203				369
N				161	270	200
F					153	254	237	258		541
Cl						243	219	210	250	359
Br							193	178		289
I								151		213
S									213	227
Si										177

double    C       O       N       S    C 615 711 874 520 O 495 N 418 S

triple    C       N    C 812 861 N 946

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C(graphite) = C(g) ΔHº = 718 kJ/mol
a) Bond Enthalpies are defined as heat liberated (e.g., ΔHº for 2H(g) = H₂(g) is -436 kJ/mol).

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