D2h_
D2h site symmetry is used to group species into genera
====
 
family= 1 0
 
family= 1 0 new D2h genus #     1 with     2 species is 0
Nber of genera for this family=    1
 
family= 0 1
 
family= 0 1 new D2h genus #     1 with     1 species is \
Nber of genera for this family=    1
 
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Nber families=      2
Nber genera=        2
Nber species=        3
