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Compound Groups

Compound groups are groups of chemicals that share structural or chemical features. In most cases, hazard lists will assign hazards to individual substances. Compound groups are useful because in some cases, lists will instead identify a group of structurally similar compounds (such as lead compounds) as all having the same hazard. The Pharos staff is in the process of establishing and populating compound groups, and associating warnings from the hazard lists with them. The table below indicates how each compound group is populated, and what is the status of its population.
Compound Groups
COMPOUND GROUP NAME POPULATION STATUS DATE POPULATED DESCRIPTION PROFILE TYPE # MEMBERS # HAZARDS
Hydrofluorocarbons (HFCs) in Google's MRSL complete 02/12/21

This compound group was populated from the Google Manufacturing Restricted Substances Specification (v1.0) (TTD_3549)

 

fixed list 23 1
Hydrofluoroolefins (HFOs) incomplete

This compound group does not have a definition yet.

structure 3 0
Hydrogen cyanide (HCN) and cyanide salts (CN salts) incomplete

This compound group is populated by the 5 CASRN listed in the US EPA IRIS review Hydrogen Cyanide and Cyanide Salts (CASRN Various) at https://cfpub.epa.gov/ncea/iris/iris_documents/documents/subst/0060.htm. This IRIS document is reference 5 in the Prop 65 listing at https://oehha.ca.gov/media/downloads/proposition-65/chemicals/032213cnisormadl.pdf

fixed list 6 16
Hydroxy-Chlorobiphenyls incomplete This compound group has not yet been assigned a structural definition. other 0 0
Hydroxylamine salts in progress This compound group is defined by the SMILES string '[NH3+]O.[*-]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. other 0 1
Inks containing 30% acrylic acid, 30% hydroxy-propanoic acid CAS# 79-33-4, 25% bronze powder (copper CAS # 7440-50-8 and tin CAS #7440-31-5, 10% ethanol CAS # 64-17-5 and 4% white spirit. [79-10-7, 79-33-4, 7440-50-8, 7440-31-5, 64-17-5] 0 1
Inorganic Ammonium Salts complete 08/01/18

This compound group is defined by the SMILES string '[NH4] subtracting [NH4].C'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 277 4
Inorganic chloramines incomplete

This compound group has not yet been assigned a structural definition.

The following three SMARTS strings would be expected to capture all chloramines but there are unknown errors when searching PubChem

[ND1][ClD1] plus

[ClD1][ND2][ClD1] plus

[ClD1][ND3]([ClD1])[ClD1]

For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 3 1
inorganic compounds of mercury with the exception of mercuric sulphide and those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

121 59
Inorganic cyanide compounds complete 03/12/20

This compound group was manually populated with inorganic cyanide compounds. It is based on an entry in Korea's GHS.

other 23 14
Inorganic silver, salts incomplete

This compound group has not yet been assigned a structural definition.

other 0 3
inorganic sulfites and bisulfites incomplete 09/01/20 structure 7 1
Inorganic zinc, salts in progress

This compound group is defined by the SMILES string '[ZnD0]' subtracting '[ZnD0].C' . For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 0 2
Iodinated Organic Compounds incomplete This compound group is defined by the SMILES string 'C[I]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. structure 356 4
Ioxynil salts complete 07/30/18

This compound group has not yet been assigned a structural definition.

other 11 0
Iron Oxides (MAK list of 4) complete

This compound group is populated from the MAK list.

fixed list 6 1
Iron salts (soluble) incomplete This compound group has not yet been assigned a structural definition. other 0 1
Iron-Zinc compounds incomplete

This compound group has not yet been assigned a structural definition.

structure 3 10
ISOCYANATES complete 07/19/17

This compound group is defined by the SMARTS string "[NX2:2]=[C:1]=[OX1:3]". For more information on SMARTS, see https://en.wikipedia.org/wiki/Smiles_arbitrary_target_specification.

structure 2936 3
Isoeugenol Isomers incomplete This compound group has not yet been assigned a structural definition. other 3 1
Jet Fuels, JP-4, JP-5, JP-7 and JP-8 incomplete This compound group has not yet been assigned a structural definition. other 1 0
Lasalocid, salts incomplete

This compound group has not yet been assigned a structural definition.

other 0 1
Lead carbonates incomplete This compound group has not yet been assigned a structural definition. structure 0 62
LEAD COMPOUNDS in progress This compound group is defined by the SMILES string '[Pb]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. element 1144 55
lead compounds with the exception of those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

other 960 64
Lead compounds with the exception of those specified elsewhere in Annex XVII of Regulation (EC) No 1907/2006 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

other 960 57
LEAD COMPOUNDS, ALKYL incomplete

This compound group has not yet been assigned a structural definition.

One approach would be to use the SMILES string 'C[Pb]' and remove substances containing 'c[Pb]' (lowercase specifies aromatic). There are technical challenges since PubChem doesn't seem to provide an option to distinguish between aromatic and aliphatic carbons. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 110 72
LEAD COMPOUNDS, INORGANIC in progress This compound group is defined by the SMILES string '[Pb]' and subsequently filtered to remove substances containing '[C]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. other 409 62
LEAD COMPOUNDS, ORGANIC in progress This compound group is defined by the SMILES string 'C[Pb]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. structure 235 59
Lead Compounds, Soluble incomplete

This Compound Group is populated from a list provided in the National Toxicology Program's 14th Report on Carcinogens at https://ntp.niehs.nih.gov/ntp/roc/content/profiles/lead.pdf.

"Lead compounds may be divided between those compounds that are relatively soluble in water and those that are relatively insoluble in water. Compounds are considered soluble or insoluble based on the following criteria: (1)  If a solubility constant (Ksp) is available, a compound with a value greater than or equal to the Ksp for lead chloride (1 × 10–4) is considered soluble. (2) If a Ksp is not available, a compound is considered soluble if more than 2 g of the compound dissolves in 100 mL of water. (3) If no numeric solubility data are available, the compounds are considered soluble or insoluble according to the general rules of solubility. The major soluble lead compounds are lead acetate, lead acetate trihydrate, lead chloride, lead nitrate, and lead subacetate"

6 56
Lead sulphates incomplete This compound group has not yet been assigned a structural definition. structure 0 62
Lobeline and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
long-chain perfluoroalkyl sulfonate (C6 and higher) incomplete

This compound group was populated by a substructure search in PubChem using the SMILES string for PFHS (perfluorohexanesulfonate), replacing terminal CF3 with CF2 to allow for longer chain lengths:

C(C(C(C(F)(F)S(=O)(=O)[O-])(F)F)(F)F)(C(C(F)F)(F)F)(F)F

structure 96 28
long-chain perfluorocarboxylic acids (C8 and higher) incomplete

This compound group was populated by a substructure search in PubChem using the SMILES string for PFOA, but replacing the terminal CF3 with CF2 to allow for longer chains:

C(=O)(C(C(C(C(C(C(C(F)F)(F)F)(F)F)(F)F)(F)F)(F)F)(F)F)O

Esters and ethers were manually removed.

structure 78 37
Lubricating oils (petroleum), various treated, extracted fracions, Baseoil - unspecified incomplete This compound group has not yet been assigned a structural definition. other 14 0
Lubricating oils, - used, distilled, refined used, and treated fractions incomplete This compound group has not yet been assigned a structural definition. other 7 0
Lysergide and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
magnesium alkyls incomplete

This compound group has not yet been assigned a structural definition.

other 0 3
magnesium salts, fatty acids, C16-18 and C18 unsaturated, branched and linear incomplete

This compound group has not yet been assigned a structural definition.

other 0 1
Malachite green salts incomplete

This compound group has not yet been assigned a structural definition.

other 0 5
Manganese Compounds complete 08/09/18

This compound group is defined by the SMILES string '[Mn]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

element 614 6
Manganese Compounds, soluble incomplete This compound group has not yet been assigned a structural definition. other 0 7
Mannomustine and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
mecoprop-P and its salts in progress 06/23/23

ECHA defined chemical group

fixed list 1 4
Medium-chain chlorinated paraffins (MCCP) complete 02/27/23

UVCB substances consisting of more than or equal to 80% linear chloroalkanes with carbon chain lengths within the range from C14 to C17

ECHA chemical group parent

4 15
Mefeclorazine and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Mephenesin and its esters incomplete This compound group has not yet been assigned a structural definition. structure 1 1
MERCURY COMPOUNDS in progress This compound group is defined by the SMILES string '[Hg]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. element 1484 49
MERCURY COMPOUNDS, ALKYL incomplete

This compound group has not yet been assigned a structural definition.

Substructure searches in PubChem cannot easily distinguish between aliphatic and aromatic carbons. If it could, the compound group would be defined by the SMILES string 'C[Hg]' and subsequently filtered to remove substances containing 'c[Hg]' (lowercase specifies aromatic). For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 486 52
Mercury Compounds, Alkyloxyalkyl and aryl mercury compounds incomplete

The list can be derived from the PIC Rotterdam Convention Annex III tables http://www.pic.int/Default.aspx?tabid=1132.

structure 30 52
MERCURY COMPOUNDS, INORGANIC in progress This compound group is defined by the SMILES string '[Hg]' and subsequently filtered to remove substances containing '[C]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. other 130 53
Mercury Compounds, Methylmercury incomplete This compound group is defined by the SMILES string '[CH3][Hg]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. structure 7 54
MERCURY COMPOUNDS, ORGANIC in progress This compound group is defined by the SMILES string 'C[Hg]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system. structure 997 51
Mercury, organic compounds (MAK) complete

MAK provides the following criteria for the organic mercury compounds it flags as hazardous. This compound group is defined by the SMILES/SMARTS string "C[Hg]" and populated from a substructure search of PubChem.

"Organomercury compounds are characterized chemically by the covalent binding of one or two alkyl or aryl groups and covalent or ionic binding of a group such as halide,hydroxide, acetate, nitrate or phosphate to the mercury atom."

https://onlinelibrary.wiley.com/doi/10.1002/3527600418.mb743997orge0015

structure 965 53
Mescaline and its salts, 3,4,5-Trimethoxyphenethylamine incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Metal salts of 2-ethylhexanoic acid complete 05/22/23

ECHA defined chemical group

fixed list 9 8
metal salts of thiocyanic acid incomplete

This compound group has not yet been assigned a structural definition.

structure 1 0
metal salts of thiocyanic acid, with the exception of those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

other 0 5
Metethoheptazine and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Metformin and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Methacrylates incomplete

This compound group is defined by the SMILES string 'CC(=C)C(=O)OC'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

other 36 2
Methapyrilene and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Metheptazine and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Methoxychlor complete 11/27/24

“Methoxychlor” refers to any possible isomer of dimethoxydiphenyltrichloroethane or any combination thereof.

fixed list 3 2
Methyl-phenol Compounds - Apple RSS complete 06/23/25 fixed list 4 1
Methylarsenic compounds complete

This compound group is defined by a substructure search of PubChem the SMILES/SMARTS string "[As][CH3]". The setting "Remove any explicit hydrogens before searching" was deselected from the substructure search.

structure 398 45
METHYLENE DIPHENYL DIISOCYANATE (MDI) COMPOUNDS incomplete This compound group has not yet been assigned a structural definition. other 15 4
METHYLHYDRAZINE SALTS in progress

This compound group is defined by the SMILES string '[CH3][NH][NH2]' or the SMARTS string '[CD1][ND2][ND1]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

structure 1 8
Methylphenidate and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
methylphenylenediamines, their n- substituted derivatives and their salts 8 1
Methyprylon and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Michler's ketone / base - OEKO-TEX complete fixed list 2 0
Mineral wool, with the exception of those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 [with alkaline oxide and alkali earth oxide content greater than 18 % by weight] incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

0 3
Molybdenum Compounds complete 08/09/18

This compound group is defined by the SMILES string '[Mo]'. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

element 391 4
Monensin, salts incomplete

This compound group has not yet been assigned a structural definition.

other 0 1
Mono- and di-phthalate esters with linear and/or branched alkyl moieties with at least one longest continuous carbon chain counted from the ester function corresponding to C4-C6 and/or with C6 cyclic saturated carbon chains and/or with unsaturated hydrocarbyl moieties incomplete structure 0 1
monoalkyl or monoaryl or monoalkyaryl esters of methacrylic acid incomplete

This compound group has not yet been assigned a structural definition.

other 1 0
monoalkyl or monoaryl or monoalkyaryl esters of methacrylic acid with the exception of those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

0 0
monoalkyl or monoaryl or monoalkylaryl esters of acrylic acid incomplete

This compound group has not yet been assigned a structural definition.

other 1 0
monoalkyl or monoaryl or monoalkylaryl esters of acrylic acid with the exception of those specified elsewhere in Annex VI of Regulation (EC) No 1272/2008 incomplete

This compound group is populated by taking the more general compound group and subtracting the chemicals found in the relevent Annex.

other 0 4
Monoalkylamines, monoalkanolamines and their salts 18 1
Monobromobiphenyls (MonoBBs) complete 09/05/25 fixed list 3 51
Monobromodiphenylethers (MonoBDEs) complete 09/05/25 fixed list 3 41
Monobutyltin compounds in progress

This compound group is defined by the SMILES string '[Sn][CH2][CH2][CH2][CH3]' subtracting compounds with 2+ butyl ligands. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

structure 0 29
Monohalomethanes complete

This compound group is composed of four chemicals so no substructure search is needed to populate it

other 6 2
Monometharsonic acids complete

This compound group is defined by A PubChem Substructure search of the SMILES/SMARTS string "[CH3][As](=O)(O)O". The setting "Remove any explicit hydrogens before searching" was deselected from the substructure search. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

 

 

structure 34 45
Monomethyltin derivatives complete 07/26/18

This compound group is defined by the SMILES string '[Sn][CH3]' subtracting compounds with 2+ methyl ligands. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

structure 95 26
Monooctyltin compounds in progress

This compound group is defined by the SMILES string '[Sn][CH2][CH2][CH2][CH2][CH2][CH2][CH2][CH3]', then subtracting compounds with 2+ octyl ligands. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

structure 0 28
Monophenyltin derivatives complete 07/26/18

This compound group is defined by the SMILES string '[CH]1=[CH][CH]=C([CH]=[CH]1)[Sn]', then subtracting compounds matching diphenyltin. For more information on SMILES, see https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_system.

structure 70 28
Morpholine and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
N-5-Chlorobenzoxazol-2-ylacetamide and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
N-Alkyl toluidine incomplete

This compound group has not yet been assigned a structural definition.

other 0 5
N-Alkyl toluidine, salts incomplete

This compound group has not yet been assigned a structural definition.

Because of the heterogeneity of the alkyl groups, populating this group through a structural search may not be feasible. As a starting point, the following three structures get close but do not constrain the alkyl group properly (o, m, p): [CH3]C1=C([CH1]=[CH1][CH1]=[CH1]1)[ND2][CH2] plus [CH1]1=C([CH1]=C([CH1]=[CH1]1)[CH3])[ND2][CH2] plus [CH1]1=C([CH1]=[CH1]C(=[CH1]1)[CH3])[ND2][CH2]

other 3 4
N-Nitrosamines; N-nitrosatable substances - OEKO-TEX complete fixed list 15 0
n-substituted derivatives of p-phenylenediamine and their salts 4 1
N,N-bis(2-Chloroethyl)methylamine N-oxide and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
N,N''-bis(4-Chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecanediamidine digluconate, Chlorhexidine and its salts, Chlorhexidine gluconate incomplete This compound group has not yet been assigned a structural definition. structure 3 1
Nalorphine, its salts and ethers incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Naphazoline and its salts incomplete This compound group has not yet been assigned a structural definition. structure 1 1
Naphtha (petroleum), treated fractions, - unspecified incomplete This compound group has not yet been assigned a structural definition. other 64 0