scattering angle 2 u03b8 theta x axis the x ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed here the space group sg pnma 62 and the lattice parameters from xrd refinement are consistent with the olivine structure the values are a 10 2883 u00e5 0 0020 b 5 9759 0 0037 c 4 6717 u00e5 0 0012 0 0072 cell volume 287 2264 u00e5 3 0 0685 density p 3 605 g cc zero 0 452 0 003 peak at full width half maximum pfwhm 0 21 crystallite size from xrd data 704 u00e5 the x ray pattern demonstrates that the product of the invention was indeed the nominal formula lifepo 4 the term u201c nominal formula u201d refers to the fact that the relative proportion of atomic species may vary slightly on the order of 2 percent to 5 percent or more typically 1 percent to 3 percent and that some portion of p may be substituted by si s or as and some portion of o may be substituted by halogen preferably f the lifepo 4 prepared as described immediately above was tested in an electrochemical cell the positive electrode was prepared as described above using 19 0 mg of active material the positive electrode contained on a weight basis 85 active material 10 carbon black and 5 epdm the negative electrode was metallic lithium.