Rh(111)+c(4x2)-C
2
H
3
+NO
Ethylidyne (C
2
H
3
, shown as black C and yellow H),
orders well when coadsorbed with NO (N-O shown blue-red).
The ethylidyne occupies hcp hollow sites,
while the NO occupies fcc hollow sites.
(Hydrogen positions are guessed.)
