Hydrazinium hydrogen oxalate

O. Edlund, A. Lund and A. Nillson, Hydrazine cation radical formation in y-irradiated single crystals of hydrazinium hydrogen oxalate.. Chem. Phys., 1968,49(2), 749-755. 

Nilsson A, Liminga R, Olovsson I (1968) A neutron diffraction study of hydrazinium hydrogen oxalate, N2H5HC204. Acta Chem Scand 22 719- 731... 

A similar case, i.e. a symmetric hydrogen bond becoming asymmetric on deuteration, was predicted on the basis of infrared and Raman spectra for a crystallographically symmetric hydrogen bond in hydrazinium hydrogen oxalate, N2H5HC2O4 (92) and confirmed recently by diffraction methods (156). 

Oxalic add (HjY=HOjC COgH) and its salts have been the subjects of extensive, and sometimes intensive, crystal-structure analysis for about 40 years (68—71 a). To the middle of 1970, the most detailed study of an acid oxalate was that of hydrazinium hydrogen oxalate (HgN NHg H Y ) by both X-ray (72) and neutron (73) diffraction. With two formula units in a cell of space group P2Jm, this has a Type A g structure centro-symmetric HY" ions are linked into infinite chains by "very short hydrogen bonds across centres of symmetry. Dimensions are in Table 16. This symmetry imphes that the hydrogen bonds are "trans with respect to the oxalate residue and that the carboxyl groups are parallel. Analysis shows them to be virtually coplanar. 

Table 16. Some dimensions in hydrazinium hydrogen oxalate (X = X-ray, N = neutron-diffraction results...

The simple acid salts, MHY, conform to these rules, and with rather greater regularity in that malonic acid is no longer exceptional its hydrogen-anion is nearly planar, though the oxygen atoms just maintain a proper van der Waals separation. Hydrazinium hydrogen oxalate conforms to the rules, but the potassium salt — as we have seen — is obdurately unorthodox. Acid salts of adipic acid have not yet been studied. 

Hydrazine Oxalates - Hydrazinium Hydrogen Oxalate (N2H5HC2O4) and Dihydrazinium Oxalate [(N2H5)2C204]... 

Hydrazine forms two compounds with oxalic acid, hydrazinium (1+) hydrogen oxalate, N2H5HC2O4, and dihydrazinium (l-h) oxalate, (N2H5)2C204. Dihydrazinium oxalate has not been studied extensively as compared to hydrazinium hydrogen oxalate. 

Hydrazinium hydrogen oxalate, N2H5HC2O4, has been studied extensively. It is obtained by mixing hot aqueous solutions of suitable amounts... 

The TG of hydrazinium hydrogen oxalate shows a continuous weight loss with a break at 31%. The product at this intermediate stage, when separately obtained and analyzed, is found to be insoluble in almost all common solvents, suggesting a polymeric nature of the compound. The weight loss and IR spectra of the intermediate suggests that it has a probable structure of -(NH-CO-CO-NH) - instead of an oxamide. 

Gajapathy, D., Govindarajan, S., and Patil, K.C. (1983) Thermal decomposition of hydrazinium hydrogen oxalate and dihydrazinium oxalate. Thermochimica Acta, 60, 87-92. 

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