PubChem chemical structure standardization

Table 2 Standardization modification rates

	Organic		Inorganic		Mixed		Total
	(102,177,263 successfully standardized substances)		(52,082 successfully standardized substances)		(2,064,089 successfully standardized substances)		(104,293,434 successfully standardized substances)
	Modified substances	Exclusively modified Substances	Modified substances	Exclusively modified Substances	Modified substances	Exclusively modified Substances	Modified substances	Exclusively modified Substances
Verify element	–	–	–	–	–	–	0	0
Verify hydrogens	228,654	49,436	–	–	68,629	2598	297,283	52,034
Verify functional groups	226,890	66,911	1680	1678	296,446	121,551	525,016	190,140
Verify valence	–	–	–	–	–	–	0	0
Standardize annotations	–	–	–	–	–	–	0	0
Standardize valence bond	37,258,340	9,643,776	–	–	463,847	97,463	37,722,187	9,741,239
Standardize aromaticity	38,305,291	11,510,081	2	–	444,851	80,666	38,750,144	11,590,747
Standardize stereochemistry	17,614,166	9,738,948	–	–	597,317	407,022	18,211,483	10,145,970
Standardize explicit hydrogens	3190	8	–	–	3580	13	6770	21
Modified substances	45,307,338		1680		1,064,295		46,373,313
Modification rate	44.34%		3.23%		51.56%		44.46%

Provided is the number of substances that is modified in each standardization step on the PubChem Substance database as well as the number of substances that is modified exclusively in a given step. The total numbers of substances for every substance class (organic, inorganic, mixed) differ from those provided in Table 1 because structures rejected by standardization were not included in the modification analysis

ISSN: 1758-2946