Carbon–nitrogen bond

A carbon–nitrogen bond is a covalent bond between carbon and nitrogen and is one of the most abundant bonds in organic chemistry and biochemistry.^[1]

Nitrogen has five valence electrons and in simple amines it is trivalent, with the two remaining electrons forming a lone pair. Through that pair, nitrogen can form an additional bond to hydrogen making it tetravalent and with a positive charge in ammonium salts. Many nitrogen compounds can thus be potentially basic but its degree depends on the configuration: the nitrogen atom in amides is not basic due to delocalization of the lone pair into a double bond and in pyrrole the lone pair is part of an aromatic sextet.

Similar to carbon–carbon bonds, these bonds can form stable double bonds, as in imines, and triple bonds such as nitriles. Bond lengths range from 147.9 pm for simple amines to 147.5 pm for C-N= compounds such as nitromethane to 135.2 pm for partial double bonds in pyridine to 115.8 pm for triple bonds as in nitriles.^[2]

A CN bond is strongly polarized towards nitrogen (the electronegativities of C and N are 2.55 and 3.04, respectively) and subsequently molecular dipole moments can be high: cyanamide 4.27 D, diazomethane 1.5 D, methyl azide 2.17, pyridine 2.19. For this reason many compounds containing CN bonds are water-soluble.

Nitrogen functional groups

Chemical class	Bond order	Formula	Example	Avg. C–N bond length (Å)^[3]
Amines	1	R₂C-NH₂	Methylamine	1.469 (neutral amine) 1.499 (ammonium salt)
Aziridines	1	CH₂NHCH₂	Mitomycin	1.472
Azides	1	R₂C-N₃	phenyl azide
Anilines	1	Ph-NH₂	Anisidine	1.355 (sp² N) 1.395 (sp³ N) 1.465 (ammonium salt)
Pyrroles	1		Porphyrin	1.372
Amides	1.2	R-CO-NR₂	Acetamide	1.325 (primary) 1.334 (secondary) 1.346 (tertiary)
Pyridines	1.5	pyr	Nicotinamide	1.337
Imines	2	R₂C=NR	DBN	1.279 (C=N bond) 1.465 (C–N bond)
Nitriles	3	R-CN	Benzonitrile	1.136
Isonitriles	3	R-NC	TOSMIC

Cyanide
Other carbon bonds with group 15 elements: carbon–nitrogen bonds, carbon–phosphorus bonds
Other carbon bonds with period 2 elements: carbon–lithium bonds, carbon–beryllium bonds, carbon–boron bonds, carbon–carbon bonds, carbon–nitrogen bonds, carbon–oxygen bonds, carbon–fluorine bonds

Compounds of carbon with other elements in the periodic table

CH																	He
CLi	CBe											CB	CC	CN	CO	CF	Ne
CNa	CMg											CAl	CSi	CP	CS	CCl	CAr
CK	CCa	CSc	CTi	CV	CCr	CMn	CFe	CCo	CNi	CCu	CZn	CGa	CGe	CAs	CSe	CBr	CKr
CRb	CSr	CY	CZr	CNb	CMo	CTc	CRu	CRh	CPd	CAg	CCd	CIn	CSn	CSb	CTe	CI	CXe
CCs	CBa		CHf	CTa	CW	CRe	COs	CIr	CPt	CAu	CHg	CTl	CPb	CBi	CPo	CAt	Rn
Fr	CRa		Rf	Db	CSg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og
		↓
		CLa	CCe	CPr	CNd	CPm	CSm	CEu	CGd	CTb	CDy	CHo	CEr	CTm	CYb	CLu
		Ac	CTh	CPa	CU	CNp	CPu	CAm	CCm	CBk	CCf	CEs	Fm	Md	No	Lr

**Chemical bonds to carbon**
Core organic chemistry	Many uses in chemistry
Academic research, but no widespread use	Bond unknown

References

↑ Organic Chemistry John McMurry 2nd Ed.
↑ CRC Handbook of Chemistry and Physics 65Th Ed.
↑ F. H. Allen, O. Kennard, D. G. Watson, L. Brammer, A. G. Orpen. Tables of bond Lengths determined by X-Ray and Neutron Diffraction. Part 1. Bond Lengths in Organic Compounds. J. Chem. Soc. Perkin Trans. II 1987, S1-S19.

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[1] Organic Chemistry John McMurry 2nd Ed.

[crc-2] CRC Handbook of Chemistry and Physics 65Th Ed.

[3] F. H. Allen, O. Kennard, D. G. Watson, L. Brammer, A. G. Orpen. Tables of bond Lengths determined by X-Ray and Neutron Diffraction. Part 1. Bond Lengths in Organic Compounds. J. Chem. Soc. Perkin Trans. II 1987, S1-S19.

Carbon–nitrogen bond

Nitrogen functional groups

See also

References