c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @coords = qw(1111111..2222222  3333333..4444444  5555555..6666666)
+;
 dd \@coords;
 ;;
 my @new_coords = map { split m{ \.\. }xms } @coords;
 dd \@new_coords;
"
["1111111..2222222", "3333333..4444444", "5555555..6666666"]

[1111111, 2222222, 3333333, 4444444, 5555555, 6666666]
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In a regex (which is what split takes as its first argument), the  . (dot) is a metacharacter meaning "match anything except a newline unless the  /s modifier is asserted, then match anything", so  . must be escaped in some way. See perlre, perlretut.