text: Anionic surfactants contain anionic functional groups at their head, such as sulfate, sulfonate, phosphate, and carboxylates.
  Prominent alkyl sulfates include ammonium lauryl sulfate, sodium lauryl sulfate (sodium dodecyl sulfate, SLS, or SDS), and the related alkyl-ether sulfates sodium laureth sulfate (sodium lauryl ether sulfate or SLES), and sodium myreth sulfate.
  Others include:
  * Alkylbenzene sulfonates
  * Docusate (dioctyl sodium sulfosuccinate)
  * Perfluorooctanesulfonate (PFOS)
  * Perfluorobutanesulfonate
  * Alkyl-aryl ether phosphates
  * Alkyl ether phosphates
  Carboxylates are the most common surfactants and comprise the carboxylate salts (soaps), such as sodium stearate.  More specialized species include sodium lauroyl sarcosinate and carboxylate-based fluorosurfactants such as perfluorononanoate, perfluorooctanoate (PFOA or PFO).