The reaction of K+ [HCr (CO) 5]-with phosphanes PR3 (R= Et, Ph, NMe2) in THF at 65° C affords the disubstituted complexes Cr (CO) 4 (PR3) 2 isolated in 57-70%. These reactions proceed via the monosubstituted hydridocarbonylchromates K+ [HCr (CO) 4PR3]-, fully