fierceness stated:
according to Rhodium: "Final Word on the HI/RP Mechanism" (Stimulants) PI3 is not formed but rather P2I4
diphosphorous tetraiodide, P2I4 is formed because the ratio of P to I2 is basically 2:2 or cancelled down to the lowest denomination, 1:1
This results from HI/RP and the liberated I2 comes from HI dissociation (2HI => I2 + H2) and from iodoephedrine + HI => meth + I2
2 P + 2 I2 ==> P2I4
The elemental combination of P + I2 will give the PI3 and, this will predominate.
2 P + 3 I2 = 2 PI3
PI3 + 3 HOH = 3HI + H3PO3