Appendix 08: Recommended Primary Standards
- Page ID
- 6644
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All compounds should be of the highest available purity. Metals should be cleaned with dilute acid to remove any surface impurities and rinsed with distilled water. Unless otherwise indicated, compounds should be dried to a constant weight at 110 oC. Most of these compounds are soluble in dilute acid (1:1 HCl or 1:1 HNO3), with gentle heating if necessary; some of the compounds are water soluble.
| Element | Compound | FW (g/mol) | Comments |
|---|---|---|---|
| aluminum | Al metal | 26.982 | - |
| antimony | Sb metal | 121.760 | - |
| - | KSbOC4H4O6 | 324.92 | prepared by drying KSbC4H4O6•1/2H2O at 110oC and storing in a desiccator |
| arsenic | As metal | 74.922 | - |
| - | As2O3 | 197.84 | toxic |
| barium | BaCO3 | 197.84 | dry at 200 oC for 4 h |
| bismuth | Bi metal | 208.98 | - |
| boron | H3BO3 | 61.83 | do not dry |
| bromine | KBr | 119.01 | - |
| cadmium | Cd metal | 112.411 | - |
| - | CdO | 128.40 | - |
| calcium | CaCO3 | 100.09 | - |
| cerium | Ce metal | 140.116 | - |
| - | (NH4)2Ce(NO3)4 | 548.23 | - |
| cesium | Cs2CO3 | 325.82 | - |
| - | Cs2SO4 | 361.87 | - |
| chlorine | NaCl | 58.44 | - |
| chromium | Cr metal | 51.996 | - |
| - | K2Cr2O7 | 294.19 | - |
| cobalt | Co metal | 58.933 | - |
| copper | Cu metal | 63.546 | - |
| - | CuO | 79.54 | - |
| fluorine | NaF | 41.99 | do not store solutions in glass containers |
| iodine | KI | 166.00 | - |
| - | KIO3 | 214.00 | - |
| iron | Fe metal | 55.845 | - |
| lead | Pb metal | 207.2 | - |
| lithium | Li2CO3 | 73.89 | - |
| magnesium | Mg metal | 24.305 | - |
| mercury | Hg metal | 200.59 | - |
| molybdenum | Mo metal | 95.94 | - |
| nickel | Ni metal | 58.693 | - |
| phosphorous | KH2PO4 | 136.09 | - |
| - | P2O5 | 141.94 | - |
| potassium | KCl | 74.56 | - |
| - | K2CO3 | 138.21 | - |
| - | K2Cr2O7 | 294.19 | - |
| - | KHC8H4O2 | 204.23 | - |
| silicon | Si metal | 28.085 | - |
| - | SiO2 | 60.08 | - |
| silver | Ag metal | 107.868 | - |
| - | AgNO3 | 169.87 | - |
| sodium | NaCl | 58.44 | - |
| - | Na2CO3 | 106.00 | - |
| - | Na2C2O4 | 134.00 | - |
| strontium | SrCO3 | 147.63 | - |
| sulfur | elemental S | 32.066 | - |
| - | K2SO4 | 174.27 | - |
| - | Na2SO4 | 142.04 | - |
| tin | Sn metal | 118.710 | - |
| titanium | Ti metal | 47.867 | - |
| tungsten | W metal | 183.84 | - |
| uranium | U metal | 238.029 | - |
| - | U3O8 | 842.09 | - |
| vanadium | V metal | 50.942 | - |
| zinc | Zn metal | 81.37 | - |
Sources: (a) Smith, B. W.; Parsons, M. L. J. Chem. Educ. 1973, 50, 679–681; (b) Moody, J. R.; Greenburg, P. R.; Pratt, K. W.; Rains, T. C. Anal. Chem. 1988, 60, 1203A–1218A.