title: Palladium disulfide
text: # Palladium disulfide
  
  Palladium disulfide is a chemical compound of palladium and sulfur with the chemical formula $PdS_2.$
  
  ## Preparation
  
  Palladium disulfide is formed when palladium(II) sulfide is heated with an excess of sulfur.
  
      PdS + S → $PdS_2$
  
  However, some starting material may remain even after heating for many months. An alternative route involves heating palladium(II) chloride and excess sulfur to 450 °C in a sealed tube, then washing the crude product with carbon disulfide. This procedure yields $PdS_2$ free of PdS.
  
  ## Structure
  
  $PdS_2$ contains sulfur-sulfur bonds so it can be thought of as a disulfide that formally consists of $S_2^{2−}$ and $Pd^{2+}$ ions. It adopts a layered crystal structure that contains square planar palladium centres and trigonal pyramidal sulfur centres.
  
  ## Related compounds
  
  A variety of other compounds in the Pd-S system have been reported, including $Pd_4S,$ $Pd_{2.8}S,$ $Pd_{2.2}S$ and PdS.
  
  