Using new data tabulations involving water, the predictive combining rule of the Hayden-O'Connell correlation for cross second virial coefficients has been reformulated with a single binary parameter for pairs. Suggestions are made to estimate this parameter when data are not available. Using the binary parameters, new solvation parameter values have been found for substances that apparently solvate with water. In addition, an additive function has been formulated to improve the descriptions at high temperatures. With these modifications, much better agreement is found with experiment than with the original relations.