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 compound by a specific equilibrium distance. If the electronic structure of the two interacting bodies is affected by the presence of one another, covalent interactions (non-ionic) also contribute to the overall energy of the compound formed. Ionic compounds are rarely purely ionic, i.e. held together only by electrostatic forces. The bonds between even the most electronegative/electropositive pairs such as those in caesium fluoride exhibit a small degree of covalency. Conversely, covalent bonds between unlike atoms often exhibit some charge separation and can be considered to have a partial ionic character. The circumstances under which a compound will have ionic or covalent