A second polymorph of bis­(dimethyl­phosphino)dimethyl­phospho­nium trifluoro­methane­sulfonate

The title compound, C₆H₁₈P₃⁺·CF₃SO₃⁻, crystallizes in two polymorphic forms in the space groups P2₁/c and Pnma. In the ortho­rhom­bic form, the two crystallographically independent mol­ecular units lie across a crystallographic mirror plane. The compound lacks traditional hydrogen-bond donors and, hence, is held together by weak C—H...O and C—H...F inter­actions, forming layers. The second polymorph was obtained as a by-product from the reaction of 1,3-bis­(2,6-dimethyl­phen­yl)-2,4-ditriflato-1,3,2,4-diaza­diphosphetidine with tetra­methyl­diphosphine.