Sum formulas

Exact chemical meaning

Ag
	Ag	pH
	Ag	solute-volatilization interference in flame spectroscopy
	Ag+	interfering substance in electroanalytical chemistry
AgBr
	AgBr	molecular rearrangement
AgCl
	AgCl	pH
	AgCl	gravimetric method
AgI
	β-AgI	polymorphic transition
	AgI	crystalline electrodes
	α-AgI	polymorphic transition
AgNO3
	AgNO3	gravimetric method
Ag2S
	Ag2S	crystalline electrodes
Al
	Al	solute-volatilization interference in flame spectroscopy
AlCl3
	AlCl3	ionization
AlNb3
	Nb3Al	superconducting transition
Al2
	2Al3+	mean activity of an electrolyte in solution
Al2MgO4
	MgAl2O4	solute-volatilization interference in flame spectroscopy
Ar
	Ar+	diamond by CVD
	Ar	gas-filled phototube
	Ar	excimer lamp
	Ar+	diamond-like carbon films
	Ar	cryogenic sampling
	Ar	Penning gas mixture
ArHOSe
	ArSeOH	selenenic acids
Ar2
	Ar2	excimer lamp
As
	As	photoconductive detector
	As	poison in catalysis
AsF5
	AsF5	dopant
AsH2
	H2As+	arsanylium ions
AsH2O
	H2As(=O)+	arsanylium ions
AsH2O2
	HAs(OH)2	arsonous acids
AsH3
	AsH3	arsines
	AsH3	arsanes
AsH3O
	H2AsOH	arsinous acids
	H3As=O	arsine oxides
AsH3O2
	AsH3O2	arsinic acids
AsH3O3
	AsH3O3	arsonic acids
AsH4
	(H4As+)	onium compounds
AsH5
	AsH5	arsoranes
As3H5
	H2AsAsHAsH2	arsanes
As3H11
	H4AsAsH3AsH4	arsanes
Au
	Au	disproportionation
	197Au	nuclear quadrupole moment (spectroscopic)
AuFe
	Au–Fe	spin-glass transition
B
	B	organically modified silica
BH
	HB+	heteroconjugation
	HB:	carbene analogues
BH6N
	H3NBH3	dative bond
BN
	NB	dative bond
B2BaO4
	BaB2O4	optical parametric oscillator
B2H
	B–H–B	electron-deficient bond
B2H6
	B2H6	electron-deficient bond
B5H9
	B5H9	boranes
Ba
	Ba2+	mean activity of an electrolyte in solution
BaO3Ti
	BaTiO3	ferroelectric (antiferroelectric) transition
BiH3
	BiH3	bismuthines
	BiH3	bismuthanes
BiH4
	(H4Bi+)	onium compounds
Br
	Br	excimer lamp
	Br	sulfonium compounds
	Br	addition reaction
	Br	telomerization
	Br	fragmentation
	Br	molecular rearrangement
	Br	allylic substitution reaction
	Br−	leaving group
	Br+	halonium ions
BrH
	BrH	leaving group
BrH2
	(H2Br+)	onium compounds
BrKr
	KrBr	excimer lamp
BrXe
	XeBr	excimer lamp
C
	C	multiply labelled
	C	transferases
	C	strain energy
	–C=	heteroarenes
	C	organically modified silica
	13C	chemical shift, in NMR
	C	potential-energy (reaction) surface
	C	tautomerism
	C	dipolar compounds
	C	methylotrophic microorganisms
	C	hydrogen bond in theoretical organic chemistry
	C	repulsive potential-energy surface
	12C	relative micellar mass
	12C	molecular ion in mass spectrometry
	C	spin polarization
CB
	B–C	potential-energy (reaction) surface
	BC	repulsive potential-energy surface
CBrCl3
	CBrCl3	telomerization
CBr4
	CBr4	rotator phase transition
CCaO3
	CaCO3	monotropic transition
CCl
	C–Cl	coordination
CClF3
	CF3Cl	background concentration (level) in atmospheric chemistry
CCl2
	:CCl2	carbenes
	CCl2	α-addition (alpha-addition)
CCl2F2
	CF2Cl2	background concentration (level) in atmospheric chemistry
CCl3
	Cl3C−	carbanion
	CCl3	telomerization
	Cl3C.	telomerization
	Cl3C.	chain transfer
CF
	C–F	negative hyper-conjugation
CH
	CH	strain energy
	CH	agostic
	C–H	symbiosis
	C–H	steric isotope effect
	HC…	carbynes
	CH	bicycle-pedal (BP) mechanism
	C–H	hypercoordination
	C–H	persistent
	–CH=	dipyrrins
	CH	carbaboranes
	–CH=	quinones
	C–H	σ, π (sigma, pi)
CHN
	HC≡N	isocyanides
	HN+≡C−	isocyanides
	C=NH	imines
	HC≡N	nitriles
	HC≡N	cyanides
CHNO
	HOC≡N	isocyanates
	HN=C=O	isocyanates
	HON=C:	fulminates
	HC≡N+–O−	fulminates
	HOC≡N	cyanates
CHNS
	HSC≡N	thiocyanates
CHNSe
	HSeCN	selenocyanates
CHO
	–CHO	characteristic group in organic nomenclature
CHO2
	–COOH	characteristic group in organic nomenclature
	–COOH	polyacid
CH2
	CH2	strain energy
	H2C	silylene
	CH2	insertion
	:CH2	carbenes
	H2C:	carbenes
	CH2	homoconjugation
	–CH2–	meso structures in polymers
	H2C.+	carbynium ions
	H2C.+	carbene radical cations
	CH2	tropyl radicals
	CH2	hypercoordination
	–CH2–	pyrromethenes
	CH2	tropylium ions
	H2C:	alkylidenes
	–CH2–	hydrocarbylene groups
CH2Cl
	ClCH2–	organyl groups
CH2N2
	CH2=N2	diazo compounds
	HN=C=NH	carbodiimides
	CH2=N=N	isoelectronic
CH2Na2O4
	Na2CO3·10H2O	efflorescence
CH2O
	CHOH	oxo compounds
	CHOH	prochirality
	CH2O	fragmentation
	CH2O	smog chamber in atmospheric chemistry
CH3
	CH3	allylic intermediates
	CH3	dimerization
	CH3	colligation
	CH3	bond-dissociation energy,
	CH3+	even-electron ion
	CH3	strain energy
	CH3	fragmentation
	CH3	chain reaction
	.CH3	radical (free radical)
	CH3	benzylic intermediates
	CH3(2A'2)	isogyric reaction
	CH3	abstraction
	CH3	σ, π (sigma, pi)
CH3Cl
	CH3Cl	molecular rearrangement
	CH3Cl	substitution reaction
CH3ClO2S
	CH3ClO2S	acyl halides
CH3F
	CH3F	molecular laser
CH3I
	CH3I	identity reaction
CH3IMg
	MeMgI	organometallic compounds
CH3N
	CH3N:	carbene analogues
	CH3N:	nitrenes
CH3NO2
	CH3NO2	azinic acids
	CH3NO2	carbamates
CH3NO2S
	CH3N=S(=O)2	sulfonylamines
CH3NaS
	CH3S−Na+	thiolates
CH3O
	–CH2OH	uronic acids
	CH3O+	oxylium ions
	OCH3	π-electron acceptor/donor group
CH3S
	CH3–S–	sulfenyl groups
	CH3S+	sulfenylium ions
	MeS–	organyl groups
	CH3S.	sulfenyl radicals
CH4
	CH4	multiply labelled
	CH4	reduced species
	CH4	molecular entity
	CH4	stoichiometry
	CH4	bond energy (mean bond energy)
	CH4	composition of pure air in atmospheric chemistry
	CH4(1A1)	isogyric reaction
	CH4	isotopologue
	13CH4+	isotope pattern in mass spectrometry
	CH4	isotope pattern in mass spectrometry
	12CH4+	isotope pattern in mass spectrometry
	CH4	spectator mechanism
	CH4	symbiosis
	CH4	bond-dissociation energy,
	CH4	abstraction
CH4FN
	CH4FN	negative hyper-conjugation
CH4N2O
	CH4N2O	isoureas
CH4N4
	H2NN=CHN=NH	formazans
CH4O
	CH3OH	Brønsted acid
	(CH3OH2+)	lyonium ion
	CH4O	substitution reaction
	CH4O	line formula
	CH4O	oxidative coupling
	CH4O	α-addition (alpha-addition)
	CH3OH	amphiprotic (solvent)
CH4O4
	C(OH)4	ortho acids
CH4Si
	H2Si=CH2	heteroalkenes
CH5
	CH5+	coordination number
	+CH5	alkanium ions
CH5B
	CH5B	spectator mechanism
CH5N3O
	NH2NHC(=O)NH2	semicarbazones
CH5P
	CH3PH2	phosphines
CIN
	ICN	pseudohalogens
CKN
	KCN	order-disorder transition
CKNO
	KOCN	cyanates
CN
	CN	apicophilicity
	CN−	interfering substance in electroanalytical chemistry
	–C≡N	characteristic group in organic nomenclature
	C–N	lyases
	CN−	prochirality
	CN−	order-disorder transition
	CN−	pseudohalogens
	–CN	carbonitriles
	C–N	hydrolases
	C–N	ligases (synthetases)
CNNa
	NaCN	cyanides
CNNaO
	Na+[–C≡N+O−]	fulminates
CNO
	–NCO	characteristic group in organic nomenclature
CNS
	N≡C–S−	organoheteryl groups
	SCN−	pseudohalogens
CNS2
	(SCN)2	pseudohalogens
CO
	C=O	carbonyl compounds
	C=O	oxo compounds
	CO	photodecarbonylation
	CO	isoelectronic
	CO	oxocarbons
	CO	air pollutant
	C–O	lyases
	C–O	hydrolases
	C–O	ligases (synthetases)
	–C(=O)–	quinones
CO2
	CO2	sublimation
	CO2	laser
	CO2	reduced species
	CO2	photodecarboxylation
	CO2	photophosphorylation
	CO2	molecular laser
	CO2	composition of pure air in atmospheric chemistry
	O=C=O	heterocumulenes
	CO2	acid rain in atmospheric chemistry
	O=C=O	oxocarbons
	CO2	cryogenic sampling
	CO2	sanitary land fill
	CO2	photosynthesis
	CO2	greenhouse effect in atmospheric chemistry
	CO2	carbon dioxide laser (CO2 laser)
CS
	C–S	ligases (synthetases)
CY
	C–Y	bisecting conformation (eclipsing conformation)
C2
	C–C	lyases
	C–C	eclipsing strain
	C–C	orbital symmetry
	C–C	hydrolases
	C–C	ligases (synthetases)
	C–C	photohydration
	C–C	symbiosis
C2H
	HC≡C−	carbanion
C2HNa
	NaC≡CH	acetylides
C2H2
	H2C=C:	carbenes
	H2C=C:	vinylidenes
	–CH=CH–	heteroarenes
	C2H2	flow rate in flame emission and absorption spectrometry
	C2H2	local fraction atomized, , in flame emission and absorption spectrometry
C2H2O
	CH2=C=O	heterocumulenes
	CH2=C=O	isoelectronic
C2H3
	CH2=CH–	vinylic groups
C2H3AgO2
	C2H3AgO2	molecular rearrangement
C2H3Cl
	C2H3Cl	isodesmic reaction
	:Cl–CH=CH2	conjugated system (conjugation)
C2H3ClO
	C2H3ClO	acyl halides
C2H3Cl3
	C2H3Cl3	isodesmic reaction
C2H3N
	CH3C≡N	cyanides
C2H3NS
	CH3SC≡N	thiocyanates
C2H3O
	CH3C(=O)–	organyl groups
C2H3O2
	–CH2CO2H	prochirality
	C2H3O2	ionization
	C2H3O2	proton transfer reaction
	CH3CO2−	Brønsted base
	C2H3O2	nucleophilic catalysis
C2H4
	C2H4	disproportionation
	C2H4	de Mayo reaction
	C2H4	isodesmic reaction
	C2H4	attachment
	–CH2–CH2–	meso structures in polymers
	C2H4	ene reaction
	C2H4	sorptive insertion in surface catalysis
	+CH2–+CH2	dicarbenium ions
	C2H4	hydration
	C2H4	reactive adsorption
	C2H4	negative hyper-conjugation
	C2H4	hyperconjugation
	C2H4	sudden polarization
C2H4Cl2
	C2H4Cl2	isodesmic reaction
C2H4Cl2NO
	C2H4Cl2NO	aminoxyl radicals
	(ClCH2)2N–O.	nitroxides
C2H4Cl2O
	C2H4Cl2O	α-addition (alpha-addition)
C2H4Cl3Pt
	[PtCl3(CH2=CH2)]−	chelation
C2H4F
	C2H4F	negative hyper-conjugation
	C2H4F	hyperconjugation
C2H4N
	CH3–CH=N.	iminyl radicals
C2H4O
	C2H4O	stoichiometry
C2H4O2
	C2H4O2	ionization
	CH3CO2H	Brønsted acid
	C2H4O2	nucleophilic catalysis
	CH3CO2H	prochirality
	C2H4O2	proton transfer reaction
	C2H4O2	leaving group
	C2H4O2	catalytic hydrogenolysis
C2H4O3
	CH3C(=O)OOH	per acids
	CH3C(=O)OOH	peroxy acids
C2H5
	CH3CH2+	carbenium ion
	C2H5	disproportionation
	CH3CH2–	organyl groups
C2H5Br
	13CCH5Br+.	isotopic molecular ion
	13C2H581Br+.	isotopic molecular ion
	C2H581Br+.	isotopic molecular ion
	C2H579Br	molecular ion in mass spectrometry
C2H5BrO
	BrCH2CH2OH	halohydrins
C2H5Cl
	C2H5Cl	nucleophile (nucleophilic)
C2H5N
	MeN=CH2	heteroalkenes
C2H5NO2
	H3N+CH2C(=O)O−	zwitterionic compounds/zwitterions
C2H5N3O2
	H2NNHC(=O)C(=O)NH2	semioxamazones
C2H6
	C2H6	disproportionation
	C2H6	catalytic hydrogenolysis
	C2H6	dimerization
	C2H6	pseudorotation
	CH313CH3	principal ion in mass spectrometry
C2H6CuLi
	Li+[CuMe2]−	organometallic compounds
C2H6NO
	C2H6NO	aminoxides
C2H6N2
	C2H6N2	carboxamidines
	C2H6N2	isoelectronic
C2H6N4S2
	H2NC(=NH)SSC(=NH)NH2	formamidine disulfides
C2H6O
	CH3–CH[2H]–OH	singly labelled
	CH3CH2OH	constitutional isomerism
	CH3OCH3	constitutional isomerism
	CH3CH2OH	prochirality
	CH3–CH2–[18O][2H]	mixed labelled
	C2H6O	hydration
C2H6O2
	HOCH2CH2OH	glycols
C2H6S
	MeCH2SH	thiols
C2H7
	[C2H7]+	alkanium ions
C2H7As
	CH3CH2AsH2	arsines
C2H7AsO2
	C2H7AsO2	arsinic acids
C2H7NS
	CH3CH2SNH2	amides
	C2H5SNH2	sulfenamides
C2H7S
	(CH3)2S+H	onium compounds
C2H10O3Si3
	C2H10O3Si3	cyclosiloxanes
C2N
	(CN)2	pseudohalogens
C3
	C=C=C	chirality axis
C3H2
	c-(CH2)3	homodesmotic reaction
C3H3AsO
	(CH3)3As=O	arsine oxides
C3H3Bi
	(CH3)3Bi	bismuthines
C3H3N
	CH2=CH–C≡N	conjugated system (conjugation)
C3H4
	H2C=CHCH:	carbenes
	H2C=CHC:H	vinyl carbenes
C3H4O2
	C3H4O2	de Mayo reaction
C3H5
	H2C=CHCH2+	allylic intermediates
	C3H5	delocalization
	CH3CH2C…	alkylidynes
	CH2=CHCH2	allylic groups
C3H5NO
	C3H5NO	lactams
	HOCH2CH2C≡N	cyanohydrins
C3H5NO3
	C3H5NO3	amic acids
C3H5NO3S
	C3H5NO3S	imides
C3H5NSe
	CH3CH2SeCN	selenocyanates
C3H5O
	C3H5O	contributing structure
	C3H5O	abstraction
C3H6
	+CH2CH2–+CH2	dicarbenium ions
	C3H6.+	radical ion
	C3H6	corrinoids (cobalamines, corphyrins, corrins, vitamin B12 compounds)
	H2C.–CH2–C.H2	diradicals
	CH3CH2CH:	alkylidenes
	–CH2CH2CH2–	hydrocarbylene groups
	C3H6	ene reaction
C3H6O
	C3H6O	abstraction
	C3H6O	epoxy compounds
	C3H6O	proton transfer reaction
	C3H6O	Paterno–Büchi reaction
	C3H6O	isoelectronic
	C3H6O	fragmentation
	C3H6O	dimerization
C3H6S
	CH3CH2C(=S)H	thioaldehydes
C3H7
	CH3CH2CH2+	carbenium ion
	CH3CH2C.H2	alkyl radicals
C3H7Br
	C3H7Br	molecular rearrangement
C3H7ClO
	ClCH2CH2CH2OH	halohydrins
C3H7N
	EtCH=NH	aldimines
C3H7O
	C3H7O	fragmentation
	C3H7O	proton transfer reaction
C3H8
	C3H8	catalytic hydrogenolysis
C3H8O2S
	(CH3)2CHS(=O)OH	sulfinic acids
	C2H5S(=O)2CH3	sulfones
C3H9ClP
	Cl(CH3)3P+	onium compounds
C3H9ClS
	[(CH3)3S]+Cl−	sulfonium compounds
C3H9N
	C3H9N	ammoniumyl radical ions
	NMe3	leaving group
	C3H9N	leaving group
C3H9NO
	(CH3)3N+–O−	zwitterionic compounds/zwitterions
C3H9NO2S
	C3H9NO2S	amides
C3O2
	O=C=C=C=O	heterocumulenes
	O=C=C=C=O	oxocarbons
C4H4
	3 CH2=CH2	homodesmotic reaction
C4H4N2
	C4H4N2	pyrimidine bases
	C4H4N2	heteroarenes
C4H4O2
	HO[CH2]4OH	glycols
	C4H4O2	isolated double bonds
C4H4S
	C4H4S	heteroarenes
C4H5N
	C4H5N	indicated hydrogen
C4H5NO2
	C4H5NO2	imides
C4H6
	C4H6	attachment
	C4H6	non-Kekulé molecules
	C4H6	addition reaction
	CH2=C(C.H2)2	trimethylenemethanes
	CH3–CH=C=CH2	dienes
	CH2=CH–CH=CH2	dienes
	CH2=CH–CH=CH2	conjugated system (conjugation)
	3 CH3–CH3	homodesmotic reaction
	C4H6	cheletropic reaction
	C4H6	s-cis, s-trans
C4H6Br2
	C4H6Br2	addition reaction
C4H6O
	C4H6O	oxa-di-π-methane rearrangement
C4H6O2S
	C4H6O2S	cheletropic reaction
C4H6O3
	C4H6O3	acid anhydrides
	C4H6O3	nucleophilic catalysis
C4H6O4
	C4H6O4	oxidative coupling
C4H6O6
	C4H6O6	meso-compound
C4H7Br
	C4H7Br	allylic substitution reaction
C4H7ClO2Zn
	ClZnCH2C(=O)OEt	organometallic compounds
C4H7NO
	(CH3)2C(OH)C≡N	cyanohydrins
C4H7Y
	C4H7Y	chain polymerization
C4H8
	C4H8	addition reaction
	C4H8	cycloalkanes
	C4H8	anti
	C4H8	hyperconjugation
C4H8Br2
	C4H8Br2	anti
C4H8O
	C4H8O	multiply labelled
	CH3CH2COCH3	prochirality
	C4H8O	allylic substitution reaction
C4H8S
	CH3C(=S)CH2CH3	thioketones
C4H9
	C4H9	hyperconjugation
C4H9Br
	C4H9Br	addition reaction
C4H9FO
	C4H9FO	diastereotopic
C4H9N
	C4H9N	pre-equilibrium (prior equilibrium)
C4H9O
	C4H9O	fragmentation
C4H10
	C4H10	catalytic hydrogenolysis
C4H10Mg
	Et2Mg	organometallic compounds
C4H10N
	C4H10N	pre-equilibrium (prior equilibrium)
C4H10O
	C4H10O	fragmentation
	CH3CH2OCH2CH3	ethers
	CH3CH2CHOHCH3	prochirality
	C4H10O	diastereotopic
	CH3CHOHCH2CH3	prochirality
C4H10O3
	HC(OCH3)3	ortho esters
C4H11N
	(CH3)3N+–C−H2	ylides
C4H11NO
	C4H11NO	pre-equilibrium (prior equilibrium)
C4H11O3PS
	C4H11O3PS	betaines
C4H12N2
	C4H12N2	amine imides
C4H13NO
	[(CH3)4N]+OH−	quaternary ammonium compounds
C4O4
	C4O4	oxocarbons
C5
	C5	terpenes
C5H3BrN4
	C5H3BrN4	tele-substitution
C5H4
	C5H4	nonclassical structure
	C5H4	electrocyclic reaction
C5H4N2O
	C5H4N2O	topomerization
C5H4N4
	C5H4N4	purine bases
C5H5N
	C5H5N+	organoheteryl groups
	C5H5N	nucleophilic catalysis
C5H5NO
	C5H5NO	tautomerism
C5H5NOS
	C5H5NOS	penems
C5H5N5
	C5H5N5	tele-substitution
C5H5OP
	C5H5OP	indicated hydrogen
C5H5P
	C5H5P	indicated hydrogen
C5H7NOS
	C5H7NOS	penams
C5H7O2
	C5H7O2	carbanion
C5H8
	C5H8	di-π-methane rearrangement
	3 CH3CH2CH3	homodesmotic reaction
	C5H8	sigmatropic rearrangement
	[CH2=C(CH3)CH=CH2]	terpenes
C5H8OS2
	CH3C(=O)SC(=S)CH2CH3	thioanhydrides
C5H8O2
	C5H8O2	de Mayo reaction
C5H8O3
	HC(=O)CH2CH2CH2C(=O)OH	oxo carboxylic acids
C5H8O5
	HO2CCH2CHOHCH2CO2H	prochirality
C5H8O7
	C5H8O7	pseudo-asymmetric carbon atom
C5H9Br
	C5H9Br	molecular rearrangement
C5H9N
	C5H9N	aza-di-π-methane rearrangement
C5H9NO2
	C5H9NO2	imino acids
C5H9O
	C5H9O	ambident
C5H10
	C5H10	envelope conformation
	C5H10	ene reaction
C5H10O
	C5H10O	prochirality
	C5H10O	molecular rearrangement
C5H10O2
	C5H10O2	molecular rearrangement
C5H10O4
	C5H10O4	monosaccharides
C5H11NO2
	C5H11NO2	betaines
C5H12
	Me4C	symbiosis
C5H12O4
	C(OCH3)4	ortho esters
C5H12O5
	C5H12O5	meso-compound
C5H14NO4P
	Me3N+–CH2CH2–OP(=O)(OH)O−	phospho
C5H15Ta
	TaMe5	homoleptic
C6H4
	C6H4	aryne
C6H4NS2
	C6H4NS2	Herz compounds
C6H4O2
	C6H4O2	quinones
	C6H4O2	quinhydrones
C6H5
	C6H5	aryl cations
C6H5AsCa
	CaAsPh	arsenides
C6H5I
	C6H5I	isotopic scrambling
C6H5KN2O
	PhN=NO−K+	diazoates
C6H5NO2
	C6H5NO2	electrophile (electrophilic)
C6H5N2
	C6H5N2	isotopic scrambling
	PhN+≡N	diazonium salts
C6H5N3
	PhN3	azides
C6H5Y
	C6H5Y	Hammett equation (Hammett relation)
C6H6
	C6H62+	nonclassical structure
	C6H6	Kekulé structure (for aromatic compounds)
	C6H6	electrophile (electrophilic)
	C6H6	catalytic hydrogenolysis
	C6H6	homodesmotic reaction
	3 CH2=CH–CH=CH2	homodesmotic reaction
	C6H6	fulvenes
	C6H6.−	radical ion
	C6H6.+	radical ion
C6H6NNa
	C6H6NNa	anilides
C6H6N2
	C6H6N2	quinonimines (quinone imines)
C6H6N2O
	PhN=NOH	diazoates
C6H6O
	C6H6O	valence tautomerization
	C6H6O	arene epoxides
C6H6OS
	PhSOH	sulfenic acids
C6H6O2
	C6H6O2	quinhydrones
C6H6O4
	C6H6O4	cycloaddition
C6H6O4S
	PhS(=O)2OOH	peroxy acids
C6H7
	C6H7+	arenium ions
C6H7N
	C6H5NH2	transformation
	C6H7N	isotopic scrambling
	C6H7N	ammoniumyl radical ions
C6H8
	C6H8	electrocyclic reaction
C6H8NO2P
	C6H8NO2P	amides
C6H8N2S
	PhS(=NH)NH2	sulfinamidines
C6H9Br
	C6H9Br	anti
C6H9NOS
	C6H9NOS	cephams
C6H9N3O2
	C6H9N3O2	pros in histidine nomenclature
C6H9Sb
	(CH2=CH)3Sb	stibines
C6H10
	C6H10	degenerate rearrangement
	C6H10	half-chair
	C6H10	attachment
	C6H10	carbenes
C6H10BrF
	C6H10BrF	anti
C6H10Br2NiP2
	Ni[(CH3)2PCH2CH2P(CH3)2]Br2	κ (kappa) in inorganic nomenclature
C6H10O3
	C6H10O3	tautomerism
C6H10O4
	C6H10O4	enoses
C6H10O7
	C6H10O7	uronic acids
	C6H10O7	ketoaldonic acids
C6H11BrO5
	C6H11BrO5	anomeric effect
C6H11NO
	C6H11NO	prochirality
	C6H11NO	lactams
C6H11S
	C6H11S	sulfonium compounds
C6H12
	C6H12	oxidative addition
	C6H12	chair, boat, twist
	C6H12	Paterno–Büchi reaction
	C6H12	cyclo-
C6H12O2
	C6H12O2	dimerization
C6H12O3
	C6H12O3	acetonides
C6H12O5
	C6H12O5	α (alpha), β (beta)
C6H12O6
	C6H12O6	aldoses
	C6H12O6	Haworth representation
	C6H12O6	ketoses
	C6H12O6	α (alpha), β (beta)
C6H12O7
	C6H12O7	aldonic acids
C6H12Si
	C6H12Si	di-π-silane rearrangement
C6H13NO5
	C6H13NO5	amino sugars
C6H14
	C6H14	cyclo-
C6H14LiN
	C6H14LiN	amides
C6H14N
	C6H14N	abstraction
C6H14O6
	C6H14O6	Haworth representation
C6H15B
	Et3B	organometallic compounds
C6H15N
	C6H15N	abstraction
C6N4
	C6N4	π-adduct
C7H4ClO2
	C7H4ClO2	isodesmic reaction
C7H4O3S2
	C7H4O3S2	cyclic acid anhydrides (cyclic anhydrides)
C7H5ClO2
	C7H5ClO2	isodesmic reaction
C7H5NO
	PhOCN	cyanates
C7H5O2
	C7H5O2	isodesmic reaction
C7H6
	C7H6	annulenylidenes
C7H6FeO2S
	[Fe(CO)3(C4H6SO)]	η (eta or hapto) in inorganic nomenclature
C7H6N
	C7H6N	nitrilium ions
C7H6O
	C7H6O	quinomethanes
	C7H6O	tropones
C7H6OS
	PhC(=S=O)H	sulfines
C7H6O2
	C7H6O2	isodesmic reaction
	C7H6O2	tropolones
C7H7
	C7H7	common-ion effect (on rates)
	C7H7	benzylic intermediates
	(C7H72+)	mass-to-charge ratio, in mass spectrometry
	C7H7+	tropylium ions
	C7H7	hyperconjugation
C7H7Br
	C7H7Br	leaving group
C7H7BrO
	C7H7BrO	cine-substitution
C7H7Cl
	C7H7Cl	common-ion effect (on rates)
C7H7NO
	C7H7NO	amides
C7H7NS
	PhC(=S)NH2	thio
C7H8
	C7H8	cycloaddition
	C7H8	catalytic hydrogenolysis
	C7H8	hyperconjugation
	C7H8	tropilidenes
	C7H8	catalytic dehydrocyclization
C7H8NO
	C7H8NO	nucleophilic catalysis
C7H8O
	C7H8O	common-ion effect (on rates)
C7H9N
	C7H9N	catalytic hydrogenolysis
C7H9NO
	C7H9NO	cine-substitution
C7H9NOS
	PhS(=O)NHCH3	sulfinamides
C7H9NO2S
	PhS(=O)2NHCH3	sulfonamides
C7H10BrF
	C7H10BrF	endo, exo, syn, anti
C7H12
	C7H12	anti
C7H12ClN
	C7H12ClN	acyl halides
C7H14N2
	C7H14N2	carboxamidines
C7H14O
	C7H14O	Norrish Type II photoreaction
C7H14O6
	C7H14O6	anomeric effect
C7H16
	C7H16	catalytic dehydrocyclization
C8H4O
	C8H4O	heteroarynes
C8H5NO
	C8H5NO	cyanides
C8H6CrO
	[Cr(CO)4(C4H6)]	η (eta or hapto) in inorganic nomenclature
C8H6S2
	C8H6S2	isolated double bonds
C8H8
	C8H8	chain reaction
	C8H8	non-Kekulé molecules
	C8H8	chain transfer
	C8H8	quinomethanes
	C8H8	alternant
	C8H8	polyhedranes
C8H8ClNO
	C8H8ClNO	molecular rearrangement
C8H8O4
	C8H8O4	polyketides
C8H8O4S
	C8H8O4S	acid anhydrides
C8H9
	(C8H9+)	homoaromatic
C8H9ClO
	PhCH(OH)CH2Cl	halohydrins
C8H9N
	PhCH=NMe	aldimines
C8H9NO
	C6H5NHCOCH3	transformation
	C8H9NO	molecular rearrangement
	C8H9NO	anilides
C8H10S
	C8H10S	leaving group
C8H11ClO
	C8H11ClO	α (alpha), β (beta)
C8H11NOS
	(CH3)2S(=O)=NPh	sulfoximides
C8H12
	C8H12	electrocyclic reaction
	C8H12	propellanes
C8H12N
	C8H12N	aminium ions
C8H12O5
	C8H12O5	tautomerism
C8H14
	C8H14	planar chirality
C8H14O4
	C8H14O4	monosaccharides
C8H16
	C8H16	tub conformation
	C8H16	crown conformation
	C8H16	extrusion transformation
C8H16N2
	C8H16N2	extrusion transformation
C8H18
	C8H18	catalytic hydrogenolysis
C8H18O
	C8H18O	zig-zag projection
C8H20N
	(CH3CH2)4N+	onium compounds
C8K
	C8K	intercalation reaction
C9H5N
	C9H5N	heteroarynes
C9H6O2
	C9H6O2	isocoumarins
	C9H6O2	coumarins
C9H8Cl3
	C9H8Cl3	chain transfer
C9H8N2
	C9H8N2	dipyrrins
C9H10O
	C9H10O	molecular rearrangement
C9H10O2
	C9H10O2	leaving group
	C9H10O2	catalytic hydrogenolysis
C9H12
	C9H12	π-adduct
C9H12S
	(CH3)2S=CHPh	ylides
	(CH3)2S+–C−HPh	ylides
C9H14
	C9H14	Bredt's rule
C9H14O4
	C9H14O4	tautomerism
C9H16
	C9H16	spiro compounds
C9H16O2
	C9H16O2	tritactic polymer
C9H18O
	C9H18O	Paterno–Büchi reaction
C9H19NO4
	C9H19NO4	glycosylamines
C10
	C10	monoterpenoids
	C10	terpenes
C10H6
	C10H6	dehydroarenes
C10H8
	C10H8	fulvalenes
	C10H8	alternant
C10H8O
	C10H8O	phenols
C10H10
	C10H10	non-Kekulé molecules
	C10H10	polyquinanes (polyquinenes)
C10H14NO
	C10H14NO	amidium ions
C10H15NS
	(C2H5)2S=NPh	sulfimides
C10H16
	C10H16	electrocyclic reaction
	C10H16	ring assembly
C10H18
	C10H18	cis-trans isomers
C10H20
	C10H20	iridoids
C11H6O3
	C11H6O3	furocoumarins
C11H12O4
	C11H12O4	acylals
C11H14
	C11H14	hula-twist (HT) mechanism
	C11H14	bicycle-pedal (BP) mechanism
C12H8
	C12H8	ring assembly
C12H8Cl2
	C12H8Cl2	meso-compound
C12H10
	C12H10	ring assembly
C12H10N2
	PhN=NPh	azo compounds
C12H10N2O
	C12H10N2O	azoxy compounds
C12H10OS
	Ph2S=O	sulfoxides
C12H10O5S2
	PhS(=O)2OS(=O)2Ph	sulfonic anhydrides
C12H12N2S
	Ph2S(=NH)2	sulfonediimines
C12H14
	C12H14	anti
C12H24O6
	C12H24O6	crown
C12O9
	C12O9	oxocarbons
C13H10O
	Ph2C–O.−	radical ion
C13H12O2
	C13H12O2	bisphenols
C13H13N3
	PhN=N–NPhMe	diazoamino compounds
C13H13OP
	(Ph)2POCH3	esters
C13H14
	C13H14	spiro compounds
C13H14O4
	C13H14O4	cycloaddition
C13H16O7
	C13H16O7	glycosides
C14H10
	C14H10	quinarenes
	C14H10	acenes
C14H10O
	C14H10O	epoxy compounds
C14H10OS2
	C14H10OS2	acid anhydrides
C14H10O9
	C14H10O9	depsides
C14H12
	C14H12	cycloaddition
C14H12N6O3
	C14H12N6O3	folates
C14H24
	C14H24	propellanes
C15
	C15	sesquiterpenoids
	C15	terpenes
C15H10O2
	C15H10O2	flavonoids (isoflavonoids and neoflavonoids)
C15H11O
	C15H11O	anthocyanidins
C15H16N
	(p-Me2NC6H4)2CHPh	leuco bases
C16H10
	C16H10	ortho- and peri-fused (polycyclic compounds)
C16H14O
	PhC(=O)CH=C(CH3)Ph	dypnones
C16H16
	C16H16	cyclophanes
C17H16Cl3
	C17H16Cl3	chain transfer
C17H21NO4
	C17H21NO4	pseudo-asymmetric carbon atom
C17H21N2
	C17H21N2	cyanine dyes
C17H28
	C17H28	steroids
C18H12
	C18H12	ortho-fused (polycyclic compounds)
C18H14
	C18H14	quinarenes
C18H34O9
	C18H34O9	in-out isomerism
C18H36N2O6
	C18H36N2O6	cryptand
C19H12
	C19H12	ortho- and peri-fused (polycyclic compounds)
C19H14N4
	C19H14N4	tetrapyrroles
C19H14O5S
	C19H14O5S	sulfonphthaleins
C19H15
	C19H15	fragmentation
C19H16
	C19H16	bicycle rearrangement
C19H17P
	Ph3P+–C−H2	ylides
	Ph3P+=CH2	ylides
C19H22N4
	C19H22N4	corrinoids (cobalamines, corphyrins, corrins, vitamin B12 compounds)
C19H30
	C19H30	cyclo-
C19H32
	C19H32	cyclo-
	C19H32	abeo-
	C19H32	seco-
C19H32O
	C19H32O	α (alpha), β (beta)
C19H34
	C19H34	seco-
C20
	C20	prostaglandins
	C20	leukotrienes
	C20	terpenes
	C20	diterpenoids
	C20	icosanoids
C20H12O5
	C20H12O5	xanthene dyes
C20H14N4
	C20H14N4	porphyrins
C20H14O4
	C20H14O4	phthaleins
C20H16O2
	C20H16O2	fragmentation
C20H19OP
	C20H19OP	betaines
C20H20O5
	C20H20O5	lignans
C20H38O2
	C20H38O2	prostaglandins
C22H23ClN2O8
	C22H23ClN2O8	tetracyclines
C22H26O6
	C22H26O6	lignans
C23H22O6
	C23H22O6	rotenoids
C25
	C25	terpenes
	C25	sesterterpenoids
C26H16
	C26H16	helicenes
	C26H16	helicity
C27H54N2
	C27H54N2	in-out isomerism
C30
	C30	terpenes
	C30	triterpenoids
C30H42O
	C30H42O	carotenoids
C38H24Cl4
	C38H24Cl4	biradical
C40
	C40	terpenes
	C40	carotenoids
	C40	tetraterpenoids
C40H56
	C40H56	retro
	C40H56	carotenoids
C40H56O2
	C40H56O2	carotenoids
C41H29NO
	C41H29NO	Dimroth–Reichardt parameter
Ca
	Ca2+	interfering substance in electroanalytical chemistry
	Ca2+	selectivity coefficient, in ion exchange chromatography
	Ca2+	ionic conductivity
CaFeO3
	CaFeO3	disproportionation
Cd
	Cd	resonance lamp
CdHe
	HeCd	ion laser
CdHgTe
	HgCdTe	photoconductive detector
CdS
	CdS	pressure-induced transition
	CdS	photoconductive detector
Cl
	Cl	abstraction
	Cl−	pH
	Cl	apicophilicity
	–Cl	characteristic group in organic nomenclature
	Cl−	gas sensing electrode
	Cl−	nucleofuge
	Cl	Herz compounds
	Cl	chain reaction
	Cl−	Brønsted base
	Cl	substitution reaction
	Cl.	chain reaction
	Cl	excimer lamp
	Cl−	selectivity coefficient, in ion exchange chromatography
	Cl	nucleophile (nucleophilic)
	Cl.	radical (free radical)
	Cl	common-ion effect (on rates)
	Cl+	halonium ions
	Cl	ionization
	Cl−	gravimetric method
	Cl	photolysis
	Cl−	conjugate acid–base pair
ClCs
	CsCl	thermally-induced transition
	CsCl	structural transition
	CsCl	first-order phase transition
	CsCl	dilational (dilatational) transition
ClH
	HCl	oxoacids
	ClH	reaction path degeneracy
	HCl	Brønsted acid
	ClH	isotope exchange
	ClH	molecular rearrangement
	HCl	levelling effect
	ClH	abstraction
	HCl	internal filling solution of a glass electrode
	HCl	conjugate acid–base pair
ClHO
	HOCl	oxoacids
ClHO4
	HClO4	levelling effect
ClH2
	(H2Cl+)	onium compounds
ClH4N
	NH4Cl	structural transition
ClK
	KCl	membrane emf
	KCl	Donnan emf (Donnan potential)
ClKr
	KrCl	excimer lamp
ClLiO4
	LiClO4	special salt effect
ClNa
	NaCl	pressure-induced transition
	NaCl	thermally-induced transition
	NaCl	structural transition
	NaCl	first-order phase transition
ClXe
	XeCl	excimer lamp
	XeCl	excimer laser
Cl2
	Cl2	gas sensing electrode
	Cl2	polarizability
	2Cl−	mean activity of an electrolyte in solution
	Cl2	excimer lamp
Cl2F
	(Cl2F+)	onium compounds
Cl2Zn
	ZnCl2	activated carbon
Cl4Rb2Zn
	Rb2ZnCl4	commensurate–incommensurate transition
Co
	Co3+	spin-state transition
CoLaO3
	LaCoO3	spin-state transition
Cr
	Cr3+	solid state lasers
	Cr3+	ruby laser
Cu
	Cu	Penning gas mixture
CuI
	CuI	chelation
CuMn
	Cu–Mn	spin-glass transition
CuZn
	CuZn	second-order transition
F
	F	apicophilicity
	F	negative hyper-conjugation
	F	hydrogen bond
	F	excimer lamp
	F	branching ratio
	F+	halonium ions
	F	hyperconjugation
FH
	HF	molecular laser
	HF	superacid
	HF	chemical laser
	HF	branching ratio
FHO3S
	HSO3F	superacid
FH2
	(H2F+)	onium compounds
FKr
	KrF	excimer laser
	KrF	liquid ion laser
F2P
	Fap–P–Fap	hypervalency
F5P
	PF5	hypervalency
	PF5	polytopal rearrangement
F5Sb
	SbF5	superacid
F6S
	SF6	air mass in atmospheric chemistry
F6U
	UF6	gaseous diffusion separator in atmospheric chemistry
Fe
	Fe3+	Verwey transition
	Fe2+	Verwey transition
	Fe	exchange-inversion transition
	Fe3+	order-disorder transition
	Fe2+	Fenton reaction
	Fe3+	Fenton reaction
	57Fe	quadrupole splitting in Mössbauer spectroscopy
	Fe3+	equivalent entity
	Fe2+	oxidized species
	Fe3+	oxidized species
	Fe	oxidized species
	57Fe	nuclear quadrupole moment (spectroscopic)
	Fe	spin crossover
	FeII	spin crossover
	FeIII	salt form of an ion exchanger
	FeII	salt form of an ion exchanger
FeLiO2
	LiFeO2	order-disorder transition
FeMo
	Mo–Fe	spin-glass transition
FeRh
	FeRh	exchange-inversion transition
Fe2O3
	α-Fe2O3	Morin transition
Fe3O4
	Fe3+[Fe3+Fe2+]O4	Verwey transition
H
	H	hyperconjugation
	H+	leaving group
	H+	general acid–base catalysis
	H	carbene analogues
	H	selenides
	H	bismuthines
	H+	pH
	H	selenoxides
	H	oxime O-ethers
	H+	extraction (equilibrium) constant
	H	nucleophilic catalysis
	H−	hydron
	H+	hydron
	H	hydron
	H	multiply labelled
	H+	gas sensing electrode
	2H	deuterium
	2H−	deuterium
	2H+	deuterium
	H	tautomerism
	H	hydrogen
	H	selones
	H+	electrofuge
	H	urethanes (urethans)
	H	extended Hammett equation
	H	ketones
	H	ketoximes
	H	Schiff bases (Schiff's bases)
	H	hemiketals
	H	sulfenyl radicals
	H+	isoionic
	H+	ligands
	H+	catalytic coefficient
	H	hemiaminals
	H	stibines
	H	tellurides
	H	ethers
	1H	chemical shift, in NMR
	2H	deuteron
	H+	tautomerism
	H	thioethers
	H	dual substituent-parameter equation
	H	azomethines
	H	thioketone S-oxides
	H	pseudo acids
	H	branching chain reaction
	H	imines
	1H	aromatic
	3H	electron capture detector in gas chromatography
	H	alkyl groups
	H	esters
	H	sulfenylium ions
	H	trioxides
	H	electrophile (electrophilic)
	H+	protonation constant
	H	polysulfanes
	H	nitrones
	H	selenols
	H+	Rutherford backscattering (RBS)
	H	sulfenic acids
	H+	specific acid–base catalysis
	H	thioketones
	H	diazoamino compounds
H	bond energy (mean bond energy)
H	sulfenamides
H	bond-dissociation energy,
H+	equivalent entity
H	silicones
H	gas-phase acidity
H	sulfenyl groups
H	Hammett equation (Hammett relation)
H	sulfoxides
H	gas-phase basicity
H	polysulfides
H	hydrazides
H	enols
H	alkoxyamines
H	ortho esters
H	phosphines
3H+	tritium
3H	tritium
3H−	tritium
1H	protium
1H+	protium
H+	protium
H	acetals
H	selenenic acids
H+	Haber–Weiss reaction
H	arsines
H	reaction path degeneracy
H	thiohemiacetals
H	ketals
H	fragmentation
H	thioacetals
H	sulfones
H(2S)	isogyric reaction
H	thiols
H	addition reaction
H	spin polarization
H	hemiacetals
H	Brønsted relation
H	ketimines
H+	standard hydrogen electrode
H	sulfides
H	common-ion effect (on rates)
HI
	HI	levelling effect
HLi
	HLi	topochemical reaction
	LiH	oxidation state
HN
	–NH	anion exchanger
	HN:	carbene analogues
	HN:	nitrenes
	NH	silasesquiazanes
	–NH–	silazanes
	HN	Lewis acid
	HN=	imino acids
HNO
	=NOH	hydroximic acids
HNO2
	HON=O	oxoacids
	HONO	smog chamber in atmospheric chemistry
HNO3
	HNO3	smog chamber in atmospheric chemistry
HN3
	–N=N–NH–	azimines
	HN3	azides
HO
	OH–	anion exchanger
	OH−	general acid–base catalysis
	–OH	vinylic groups
	–OH	hydrazidines
	HO	allylic substitution reaction
	–OH	characteristic group in organic nomenclature
	OH	erythro structures in a polymer
	OH−	isoionic
	HO	substitution reaction
	OH−	catalytic coefficient
	–OH	benzylic groups
	OH	phosphoglycerides
	OH−	Fenton reaction
	OH	phosphoramides
	HO	anhydro bases
	OH	oxo compounds
	–OH	cresols
	OH−	kinetic equivalence
	OH−	specific acid–base catalysis
	HO	pre-equilibrium (prior equilibrium)
	–OH	allylic groups
	HO+	oxylium ions
	OH	anilides
	OH−	Brønsted base
	–OH	sulfenamides
	HO	decay rate in atmospheric chemistry
	–OH	hydrazides
	HO.	alcohols
	–OH	alcohols
	–OH	hydroxamic acids
	HO	molecular rearrangement
	HO−	acyl species
	HO.	acyl species
	HO+	acyl species
	OH.	Fenton reaction
	OH.	Haber–Weiss reaction
	OH−	Haber–Weiss reaction
	HO	colligation
	OH	branching chain reaction
	HO	smog chamber in atmospheric chemistry
	–OH	peroxy acids
HO2
	–OOH	peroxy acids
HO3S
	–SO3H	characteristic group in organic nomenclature
	–SO3H	polyacid
HO4S
	HSO4−	Brønsted acid
	HSO4−	Brønsted base
HSi
	Si–H	agostic
	SiH	silasesquiazanes
H2
	H2	pH
	H2	gas sensing electrode
	H2	catalytic hydrogenolysis
	H2(1Σ+g)	isogyric reaction
	H2	standard hydrogen electrode
H2I
	(H2I+)	onium compounds
H2KN
	H2KN	isotopic scrambling
H2N
	NH2	amides
	–NH2	characteristic group in organic nomenclature
	NH2	phosphoglycerides
	H2N.	aminyl radicals
	(H2N:+)	nitrenium ions
H2NO
	H2N–O−	aminoxides
	H2N–O.	nitroxides
	–NHOH	hydroxamic acids
H2NP
	HP=NH	phosphazenes
H2N2
	=NNH2	hydrazidines
	H2NN:	carbene analogues
	–NHNH–	hydrazo compounds
	=NNH2	hydrazones
	HN=NH	azo compounds
H2N2O
	H2NNO	nitrosamides
H2N2O2
	O2NNH2	nitramines
H2N2S
	HN=S=NH	sulfur diimides
H2O
	H2O	oxenium ions
	H2O	common-ion effect (on rates)
	H2O	ionization
	H2O	composition of pure air in atmospheric chemistry
	H2O	temperature lapse rate in atmospheric chemistry
	H2O	Brønsted acid
	H2O	supersaturation
	H2O	Brønsted base
	H2O	oxidative coupling
	H2O	nucleophilic catalysis
	H2O	anhydro bases
	H2O	hydration
	H2O	branching chain reaction
	H2O	pre-equilibrium (prior equilibrium)
	H2O	gaseous diffusion separator in atmospheric chemistry
	H2O	Haber–Weiss reaction
	H2O	sanitary land fill
	H2O	photosynthesis
	H2O	amphiprotic (solvent)
H2O2
	HOOH	hydroperoxides
	H2O2	Fenton reaction
	H2O2	oxidation state
	H2O2	Haber–Weiss reaction
	H2O2	smog chamber in atmospheric chemistry
H2O2S
	HOSOH	oxoacids
	HS(=O)OH	sulfinic acids
H2O3
	HOOOH	trioxides
H2O3P
	–PO3H2	characteristic group in organic nomenclature
	–P(=O)(OH)2	phospho
	–P(=O)(OH)2	phosphono
	–PO3H2	polyacid
H2O3S
	HS(=O)2OH	sulfonic acids
H2O4S
	(HO)2SO2	oxoacids
	H2SO4	reduced species
	H2SO4	Brønsted acid
	H2SO4	equivalent entity
	H2SO4	oxidation state
	H2SO4	haze in atmospheric chemistry
	H2SO4	amphoteric
H2S
	H2S	hydrocracking unit
	H2S	reduced species
	SH2	bonding number
	H2S	sulfenylium ions
	H2S	acid-labile sulfur
	H2S	oxidized species
	H2S	sulfenyl groups
	H2S	sulfenyl radicals
	H2S	oxidation state
	H2S	sulfanes
	H2S	air pollutant
H2S2
	HS2H	polysulfanes
H2Se
	H2Se	selenides
H2Si
	H2Si:	silylene
	H2Si	silylene
H2Te
	H2Te	tellurides
H3N
	H3N.+	ammoniumyl radical ions
	H3N	aminiumyl radical ions
	NH3	Brønsted acid
	NH3	Rydberg state
	H3N	tele-substitution
H3NO
	H2N–OH	hydroxylamines
H3NO2
	H3NO2	azinic acids
H3NO3
	H3NO3	azonic acids
H3NO3S
	H2NS(=O)2OH	sulfamic acids
H3NS
	H2S=NH	sulfimides
H3N2
	–NHNH2	hydrazidines
	H2NN.H	verdazyl radicals
H3N3
	NH2N=NH	triazenes
H3O
	H3O+	oxonium ions
	H3O	ionization
	H3O+	Brønsted acid
	(H3O+)	onium compounds
H3OP
	H2POH	phosphinous acids
H3O2P
	HP(OH)2	phosphonous acids
	H2P(=O)OH	phosphinic acids
H3O3P
	P(OH)3	oxoacids
	HP(=O)(OH)2	phosphonic acids
H3O4P
	H3PO4	electrolytic hygrometer
H3P
	PH3	phosphines
	PH3	phosphanes
H3S
	(H3S+)	onium compounds
H3Sb
	SbH3	stibanes
	SbH3	stibines
H3Se
	(H3Se+)	onium compounds
H3Si
	H3Si–	silyl groups
	H3Si.	silyl radicals
H3Sn
	.SnH3	radical (free radical)
H3Te
	(H3Te+)	onium compounds
H4N
	(H4N+)	onium compounds
H4NP
	H3P=NH	phosphazenes
H4NY
	(NH4+)Y−	quaternary ammonium compounds
H4N2
	H2NNH2	hydrazines
H4OSi
	H3SiOH	silanols
H4P
	(H4P+)	onium compounds
H4Sb
	(H4Sb+)	onium compounds
H5NO4S
	NH4HSO4	haze in atmospheric chemistry
H5N3
	NH2NHNH2	triazanes
H5P
	PH5	phosphoranes
H6S
	SH6	bonding number
H10N2Si3
	H3SiNHSiH2NHSiH3	silazanes
He
	3He	helion
	He	atomic laser
	He+	Rutherford backscattering (RBS)
	4He	α-particle (alpha-particle)
Hg
	Hg	resonance lamp
I
	I−	identity reaction
	129I	nuclear quadrupole moment (spectroscopic)
	131I	radioiodination
	125I	radioiodination
	123I	radioiodination
	I	excimer lamp
	I+	halonium ions
IK
	IK	isotopic scrambling
IO2
	IO2	characteristic group in organic nomenclature
IXe
	XeI	excimer lamp
I2
	I2	dopant
	I2	excimer lamp
K
	K	syntectic reaction
KMnO4
	KMnO4	equivalent entity
KZn
	K-Zn	syntectic reaction
KZn13
	KZn13	syntectic reaction
Kr
	Kr	excimer lamp
	Kr	resonance lamp
	Kr	liquid ion laser
Kr2
	Kr2	excimer lamp
La
	La3+	ionic conductivity
Li
	Li+	order-disorder transition
LiMn2O4
	Li[Mn2]O4	topochemical reaction
Mg
	Mg	solute-volatilization interference in flame spectroscopy
	Mg2+	selectivity coefficient, in ion exchange chromatography
Mg2O4Si
	Mg2SiO4	reconstructive transition
MnO2
	MnO2	magnetic transition
Mn3O4
	Mn3O4	Jahn–Teller transition
N
	N	imides
	N	hydrogen bond in theoretical organic chemistry
	N	dipolar compounds
	N	hydrogen bond
	N	umpolung
	≡N	nitriles
	N	amidium ions
	N	alkoxyamines
	N	spin crossover
NO
	NO	reference procedure in analysis of trace air constituents
	–NO	nitroso compounds
	NO	emission in atmospheric chemistry
	NO	composition of pure air in atmospheric chemistry
	–N=O	isonitroso compounds
	NO+	isoelectronic
	NO	primary pollutant in atmospheric chemistry
NO2
	NO2	reference procedure in analysis of trace air constituents
	NO2+	electrofuge
	–NO2	nitro compounds
	NO2	π-electron acceptor/donor group
	NO2	composition of pure air in atmospheric chemistry
	NO2	permeation tube
	NO2	air pollutant
	NO2	electrophile (electrophilic)
NO3
	NO3−	mean activity of an electrolyte in solution
	NO3	oxidant in atmospheric chemistry
NO3Rb
	RbNO3	thermally-induced transition
N2
	N2	reference procedure in analysis of trace air constituents
	N2	cage
	=N+=N−	diazo compounds
	N2	molecular laser
	N2	photochemical nitrogen extrusion
	N2	isoelectronic
	N2	cryogenic sampling
	N2	geminate recombination
N2O
	N2O	local fraction atomized, , in flame emission and absorption spectrometry
N3
	N3	azides
	–N=N+=N−	azides
	N3−	pseudohalogens
	–N3	quinone diazides
N3Na
	NaN3	azides
Na
	Na+	mean activity of an electrolyte in solution
	Na+	interfering substance in electroanalytical chemistry
	Na	resonance lamp
	Na+	ionic conductivity
Nb3Sn
	Nb3Sn	superconducting transition
Ne
	Ne	helium–neon laser
	Ne	atomic laser
	Ne	excimer lamp
Ni
	63Ni	electron capture detector in gas chromatography
NiS
	NiS	dilational (dilatational) transition
O
	O	imides
	=O	hydrazidines
	–O–	silathianes
	=O	characteristic group in organic nomenclature
	=O	imidines
	–O–	imidines
	O2−	ligands
	=O	hydroximic acids
	O	dipolar compounds
	O	hydrogen bond
	O	tautomerism
	–O–	diamidides
	=O	diamidides
	O	hydrogen bond in theoretical organic chemistry
	–O–	silazanes
	=O	oxo compounds
	O	umpolung
	O	ylides
	O	amidium ions
	=O	hydrazones
	=O	imidic acids
	O	branching chain reaction
OP
	P–O	ligases (synthetases)
O2
	O2	biochemical (biological) oxygen demand ()
	(=O)2	sulfonediimines
	O2	singlet molecular oxygen (singlet molecular dioxygen)
	O2	spin-statistical factor (in diffusion-controlled reactions)
	O2	flow rate in flame emission and absorption spectrometry
	O2	mean free path,
	O22−	peroxides
	O2	catalase
	O2	chemical oxygen demand ()
	O2	chemical bond
	O2	Schenck-sensitization mechanism
	O2−	Haber–Weiss reaction
	O2	Haber–Weiss reaction
	O2	photosynthesis
	O2	configuration (electronic)
O2S
	SO2	oxidized species
	SO2	extraction (equilibrium) constant
	SO2	emission in atmospheric chemistry
	O2S	cheletropic reaction
	SO2	primary pollutant in atmospheric chemistry
	SO2	oxidation state
	SO2	permeation tube
	SO2	composition of pure air in atmospheric chemistry
	SO2	sink in atmospheric chemistry
	SO2	air pollutant
O2Si
	SiO2	polymorphic transition
	SiO2	displacive transition
O2Ti
	TiO2	irreversible transition
O2V
	VO2	metal–insulator transition
O2Zr
	ZrO2	martensitic transition
O3
	O3	reference procedure in analysis of trace air constituents
	O3	secondary pollution (emissions)
	O3	decay rate in atmospheric chemistry
	O3	greenhouse effect in atmospheric chemistry
O3S
	SO3	oxidized species
	SO3	oxidation state
	–(SO3−)	membrane sites in an ion-selective electrode
O3Ti2
	Ti2O3	semiconductor-metal transition
O4
	O4	chemical bond
O4S
	SO42−	Brønsted base
	SO42−	selectivity coefficient, in ion exchange chromatography
O4S3
	3SO42−	mean activity of an electrolyte in solution
O4Si
	SiO4	displacive transition
O5P2
	P2O5	electrolytic hygrometer
O5V2
	V2O5	gel
P
	P	imides
	P	umpolung
PbS
	PbS	photoconductive detector
Pt
	Pt	pH
	Pt	gas sensing electrode
S
	S	polytypic transition
	S	imides
	S	tautomerism
	S	mustards
	–S–	silathianes
	S	hydrogen bond in theoretical organic chemistry
	S	umpolung
	S	ylides
	S	poison in catalysis
	S	triple point
SZn
	ZnS	polytypic transition
S2
	S2	polysulfanes
S2Ti
	TiS2	intercalation reaction
S8
	S8	oxidation state
Se
	Se	imides
	Se	umpolung
	Se	ylides
Si
	Si	di-π-silane rearrangement
	Si	silanols
	Si	photoconductive detector
SiV3
	V3Si	superconducting transition
Sn
	119Sn	nuclear quadrupole moment (spectroscopic)
	119Sn	quadrupole splitting in Mössbauer spectroscopy
Te
	Te	imides
	Te	ylides
Ti
	Ti3+	solid state lasers
U
	239U	resonance neutrons
Xe
	Xe	excimer lamp
	Xe	resonance lamp
Xe2
	Xe2	excimer lamp
Zn
	Zn	polytypic transition
	Zn	syntectic reaction
	Zn	resonance lamp