Abstract: Molybdenum precursors with high purity and methods for purifying molybdenum precursors are provided. A method comprises obtaining a first vessel comprising a solid reagent; vaporizing at least a portion of the solid reagent to produce a vapor comprising a MoCl5 vapor and a molybdenum impurity vapor; flowing at least a portion of the MoCl5 vapor and at least a portion of the molybdenum impurity vapor to a second vessel; condensing at least a portion of the MoCl5 vapor in the second vessel to separate the MoCl5 from the molybdenum impurity; and removing at least a portion of the molybdenum impurity vapor from the second vessel to obtain a MoCl5 precursor.

Abstract: Tungsten precursors with high purity and methods for purifying tungsten precursors are provided. The method for purifying a precursor may comprise at least one of the following steps: obtaining a source vessel containing WCl4, WOCl4, and one of WCl5 or WCl6; separating the WCl5 or the WCl6 from at least a first portion of the WOCl4; separating the WCl5 or the WCl6 from at least a second portion of the WOCl4; recovering a precursor in a collection vessel; or any combination thereof.

Abstract: A precursor comprises a tungsten precursor and a carbon-containing material. The precursor comprises less than 0.02% by weight of the carbon-containing material based on a total weight of the precursor. A method for purifying a tungsten precursor may comprise at least one of the following steps: obtaining a source vessel containing a tungsten precursor and a carbon-containing material; separating the tungsten precursor from at least a first portion of the carbon-containing material; recovering a precursor in a collection vessel; or any combination thereof.