- In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions. These can be simple ions such as the sodium (Na+) and chloride (Cl−) in sodium chloride, or polyatomic species such as the ammonium and carbonate ions in ammonium carbonate. Individual ions within an ionic compound usually have multiple nearest neighbours, so are not considered to be part of molecules, but instead part of a continuous three-dimensional network. Ionic compounds usually form crystalline structures when solid.
- Thomas Jefferson (plato.standford.edu)
Scholars in general have not taken seriously Thomas Jefferson (1743–1826) as a philosopher, perhaps because he never wrote a formal philosophical treatise. Yet Jefferson was a prodigious writer, and his writings were suffuse with philosophical content. Well-acquainted with the philosophical literature of his day and of antiquity, he left behind a rich philosophical legacy in his declarations, presidential messages and addresses, public papers, numerous bills, letters to philosophically minded correspondents, and his only book, Notes on the State of Virginia.