SEMIQUANTITATIVE XRD ANALYSIS WITH THE AID OF REFERENCE INTENSITY RATIO ESTIMATES

Estimation of reference intensity ratios (k(i) or RIR) can be made on the basis of an atomic scattering function. Tests of regression equati ons for 50 compounds that predict an approximate reference intensity r atio from the easily computed scattering function have shown usefulnes s in multicomponent semiquantitative X-ray diffraction analysis. The m ethod is best applied whenever only one or two minor components of a m ulticomponent sample have no readily measurable or calculable k(i) val ues and must be estimated. Where the difference between observed and p redicted constants is large, these tests show that the ratios of true- to test-weight fractions are proportional to the corresponding k(i) r atios. The largest absolute errors occur whenever the k(i) must be pre dicted for components with medium weight fraction values. Estimation o f k(i) for components of less than 10 weight percent results in only s mall errors in both predicted component and the other components of th e sample. Where more than two components require predicted k(i) in a g iven sample, unacceptable errors for all components may result. (C) 19 98 International Centre for Diffraction Data. [S0885-7156(98)01402-X]