C., when the thiourea first formed is converted into guanidine thiocyanate, 2CS(NH2)2=HN:C(NH2)2.HCNS+H2S.
"Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 6" by Various
Examples are nickel sulphate (NiSO4.6H2O), guanidine carbonate ((CH5N3)2H2CO3), strychnine sulphate ((C21H22N2O2)2.H2SO4.6H2O).
"Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7" by Various
In vitro, the transition between the various phases is controlled by temperature, pH, denaturant agent (such as urea or guanidine).
Protein folding and heteropolymers