Hill notation wrong (still)

[CasperWA]

Actual definition:

• If carbon is present, place it first, then hydrogen if present.
• Following hydrogen, sort elements alphabetically.
• If carbon is not present, sort elements alphabetically, also if hydrogen is present.

Example of valid Hill notation formulas:

• C H₄ Cl O
• Cl H₄ O
• C Cl O

Incorrect Hill notation:

• H₄ Cl O

(See, e.g., the wikipedia entry for Hill notation.)