I tried looking for these arrows in the 3rd molecule starting from the left(Pd) online and in my notes but I couldn't find anything. Is Pd actually bonded to something?
8$\begingroup$ Aha! So the request for context was even more justified than usual, for it shed a whole new light on the entire picture. Now let me hazard a guess: this is a Pd atom surrounded by two allyl ligands, drawn by a chemist whose frivolous use of notation got them banished from the profession and severely beaten by fellow chemists on more than one occasion. $\endgroup$– Ivan NeretinJan 17 at 10:50
4$\begingroup$ That is presumably an attempt to represent an allyl anion, which exists as a resonant structure. The double bonds are actually a delocalized double bond. See for instance en.wikipedia.org/wiki/Allylpalladium_chloride_dimer $\endgroup$– Buck Thorn ♦Jan 17 at 11:50
$\begingroup$ Is this not typical use of notation in inorganic chemistry? $\endgroup$– GarrettJan 18 at 5:27
1$\begingroup$ This is a typical representation of a delocalized system when dealing with organic systems. In fact, it is in complete analogy to the structure immediately two the left. The curves associated with an allyl system are just the circles for the cyclopentadienyl system. $\endgroup$– ZheJan 18 at 14:26
2$\begingroup$ I object; it is not typical even then. You don't draw delocalized systems with double bonds all around. $\endgroup$– Ivan NeretinJan 18 at 15:34
- These are not arrows, but fragments of the molecule.
- We suspect they are supposed to mean the allyl ligands.
- This hardly qualifies as inorganic chemistry. Organometallic is probably the right word to use.
- The notation is by no means standard; I would go as far as to call it wrong, and not just a slightly-raised-eyebrow kind of wrong, but a punch-in-the-face kind. Those who want to be understood would draw the same molecule in any of the following shapes:
(There are more possible variants.)
So it goes.
1$\begingroup$ In deed, they are sandwiched metal complexes of allyl compounds. For example, looks here. $\endgroup$ Jan 18 at 20:40