while (<>) {
	if ($_=~ /^ATOM/) {

		@atom_column = split ' +', $_;

		$atom_c6 = $atom_c6.$atom_column[6];
	}

print $atom_c6 gives:

x.xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx etc

print "/n$atom_c6/n" gives:

x.xx

x.xx

x.xx

x.xx etc