The new oligophosphines [H2P(CH2)(2)](2)PH, [H2P(CH2)(2)P(H)CH2](2), and {[(H2P(CH2)(2)](2)PCH2}(2) have been made by hydrophosphination of diethyl vinylphosphonate (2) with H2P(CH2)(2)PH2 (1), using different ratios of 2/1, followed by LiAlH4 reduction of the phosphonate intermediates; the three phosphonate precursors were obtained as oils of varying purity (similar to 90-95%) in low (similar to 20%) to almost quantitative yield. The tri-, tetra-, and hexaphosphines were then treated with formaldehyde in the presence of hydrochloric acid to generate the corresponding water-soluble (hydroxymethyl)phosphonium chlorides {(HOCH2)(3)P[(CH2)(2)P(CH2OH)(2)](n)(CH2)(2)P(CH2PH)(3)}Cl-m (n = 1, m = 3; n = 2, m = 4) and {[(HOCH2)(3)P(CH2)(2)](2)P(CH2OH)CH2}(2)CI6 that were characterized by NMR spectroscopy and elemental analysis. The known (hydroxymethyl)bisphosphonium chloride [(HOCH2)(3)P(CH2)(2)](2)Cl-2 was similarly prepared from H2P(CH2)2PH2, and the determined crystal structure revealed strong hydrogen bonding between the chloride anions and the hydrogen atoms of the hydroxymethyl groups.