##############################################################################
#                                                                            #
#	                Open Babel file: aromatic.txt                            # #                                                                            #
#                                                                            #
#  Copyright (c) 1998-2001 by OpenEye Scientific Software, Inc.              #
#  Some portions Copyright (c) 2001-2005 Geoffrey R. Hutchison               #
#  Part of the Open Babel package, under the GNU General Public License (GPL)#
#                                                                            #
# SMARTS patterns with minimum and maximum pi-electrons contributed to an    #
#   aromatic system (used by typer.cpp:OBAromaticTyper)                      #
# The LAST PATTERN MATCHED is used to assign values, so that patterns should #
#   be ordered from more general to more specific                            #
#                                                                            #
##############################################################################

#PATTERN		MIN	MAX

#carbon patterns
[#6rD2]			1	1
# exo ketone or alcohol -- don't know which
[#6rD3]~!@[#8]		0	1
[#6rD2+,#6rD3+]		1	1
[#6r]=@*		1	1
[#6rD3]=!@*		1	1
# external double bonds to hetero atoms contribute no electrons to the 
# aromatic systems -- quinoid systems are non-aromatic, e.g. 1,4-benzoquinone
[#6rD3]=!@[!#6]		0	0
[#6rD3-]		2	2

#nitrogen patterns
[#7rD2]			1	2
[#7rD3]                 1       2
[#7r](-@*)-@*  		1	2
[#7rD2]=@*		1	1
[#7rD3+]		1	1
[#7rD3]=O		1	1
[#7rD2-]		2	2

#oxygen patterns
[#8r]			2	2
[#8r+]			1	1

#sulfur patterns
[#16rD2]		2	2
[#16rD2+]		1	1
[#16rD3]=!@O		2	2

#other misc patterns
# Accounts Chem Res 1978 11 p. 153
# phosphole, phosphabenzene (not v. aromatic)
[#15rD3]		2	2
# selenophene
[#34rD2]		2	2
# arsabenzene, etc. (*really* not v. aromatic)
#[#33rD3]		2	2
# tellurophene, etc. (*really* not v. aromatic)
#[#52rD2]		2	2
# stilbabenzene, etc. (very little aromatic character)
#[#51rD3]		2	2