The major industrial synthesis involves the reaction of sulfur trioxide and sulfur dichloride: This synthesis can be adapted to the laboratory by heating oleum to slowly distill the sulfur trioxide into a cooled flask of sulfur dichloride.
Other methods include syntheses from: 
*Phosphorus pentachloride:
*Chlorine and sulfur dichloride:
*Phosgene:
The second of the above four reactions also affords phosphorus oxychloride (phosphoryl chloride), which resembles thionyl chloride in many of its reactions.