Title: Biguanide
CAS Registry Number: 56-03-1
CAS Name: Imidodicarbonimidic diamide
Synonyms: guanylguanidine; amidinoguanidine; diguanide
Molecular Formula: C2H7N5
Molecular Weight: 101.11
Percent Composition: C 23.76%, H 6.98%, N 69.26%
Literature References: Preparation from dicyanodiamide: Rackmann,
Ann. 376, 169 (1910); Karipides, Fernelius,
Inorg. Synth. 7, 56, 58 (1963). Crystal structure: S. R. Ernst, F. W. Cagle,
Acta Crystallogr. 33B, 235 (1977); S. R. Ernst,
ibid. 237.
Properties: Crystals from alc, mp 130°; dec rapidly at about 142°. Sol in water, alcohol. Insol in ether, benzene, chloroform. The aq soln dec on standing or heating. Aq solns are alkaline. Biguanide is a stronger base (pK1 = 11.52; pK2 = 2.93) than ammonia (pK = 9.61).
Melting point: mp 130°
pKa: pK1 = 11.52; pK2 = 2.93; pK = 9.61
Derivative Type: Hydrochloride
Molecular Formula: C2H7N5.HCl
Molecular Weight: 137.57
Percent Composition: C 17.46%, H 5.86%, N 50.91%, Cl 25.77%
Properties: Needles, mp 235°, very sol in water, slightly sol in alc.
Melting point: mp 235°
Derivative Type: Neutral sulfate
Molecular Formula: (C2H7N5)2.H2SO4.2H2O
Molecular Weight: 336.33
Percent Composition: C 14.28%, H 5.99%, N 41.65%, S 9.53%, O 28.54%
Properties: Large crystals, sol in water.
Derivative Type: Acid sulfate
Molecular Formula: C2H7N5.H2SO4.H2O
Molecular Weight: 217.20
Percent Composition: C 11.06%, H 5.10%, N 32.24%, S 14.76%, O 36.83%
Properties: Rhombic prisms, sol in water, the soln giving an acid reaction.
Use: Sulfates in the determination of copper and nickel.
