IAEA C7 Oxalic Acids was prepared by M. Le Clercq and J. van der Plicht, by using industrially oxalic acids, one produced using the carbohydrate oxidation route in India by the Vaishali firm, Aurangabad, and synthetic oxalic acids produced using the alkaline CO_H2O synthesis by the company Rhône Poulenc, Switzerland. Both materials, one containing modern 14C levels and the other one being free of 14C, were mixed both together in desired ratios by dissolution and re crystallization at Chemie Uettikon GmbH, Lahr, Germany [1], in quantities of 150 kg. The recommended value for 14C activity of this reference material is the result of the statistical evaluation of an interlaboratory comparison [1]. For carbon stable isotope delta values, please refer to [1]. Further details can be found on the Reference Sheet.
Recommended value for C-14 activity
| Radionuclide | Recommended value [pMC] | Uncertainty(a) [pMC] | Half-Life |
| 14C | 49.53 | 0.84 | 5700 (30) y |
(a) The uncertainty is expressed as a combined standard uncertainty (coverage factor k = 1)
Reference date for decay correction: 01 January 1998
The 14C activity value is expressed in pMC (“percent Modern Carbon”) as reported in the literature [1]
References:
LE CLERCQ, M., VAN DER PLICHT, J., GRÖNING, M., New 14C reference materials with activities of 15 and 50 pMC, Radiocarbon 40 1 (1998) 295-297.
