Claude Nicolas Ledoux embraced the principle of superimposing the classic column motifs on each floor, rising from simplest to the most complex: Tuscan, Doric, Ionic, Corinthian, etc. On 26 July 1764, in the Saint-Eustache Church, Paris, Ledoux married Marie Bureau, the daughter of a court musician. A friend from Champagne, Joseph Marin Masson de Courcelles, found him a position as the architect for the Water and Forestry Department. Here between 1764 and 1770 he worked on the renovation and designs of churches, bridges, wells, fountains and schools, in Tonnerrois, Sénonais and Bassigny. Among the still extant works from this period are the bridge
Ionic radius radii. The relation between soft-sphere ionic radii, formula_2 and formula_3, and formula_1, is given by formula_5, where formula_6 is an exponent that varies with the type of crystal structure. In the hard-sphere model, formula_6 would be 1, giving formula_8. In the soft-sphere model, formula_6 has a value between 1 and 2. For example, for crystals of group 1 halides with the sodium chloride structure, a value of 1.6667 gives good agreement with experiment. Some soft-sphere ionic radii are in the table. These radii are larger than the crystal radii given above (Li, 90 pm; Cl, 167 pm). Inter-ionic separations calculated