title: Dinicotinamidium squarate.
abstract: The crystal structure determination of the dinicotinamidium squarate salt, 2C(6)H(7)N(2)O(+).C(4)O(4)(2-), is reported, with the squarate dianion residing on an inversion centre and the unique cation in a general position. Salt formation occurs by donation of two H atoms from squaric acid to the nicotinamide base. The crystal packing is derived from three types of hydrogen bonding. The primary hydrogen bond involves a squarate anion O atom and an H atom of the protonated pyridine group of the nicotinamide, with an N.O distance of 2.5760 (13) A. The second hydrogen bond involves a second anion O atom and an amide H atom, with an N.O distance of 2.8374 (14) A. Thirdly, an intermolecular interaction between two coplanar nicotinamide moieties occurs between an amide O atom and a symmetry-related amide H atom, with an N1.O3 distance of 2.8911 (15) A. These hydrogen bonds are also responsible for the planarity of the nicotinamide moiety in the salt.
authors.affiliation: Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayís University, TR-55139, Kurupelit-Samsun, Turkey. abulut@omu.edu.tr
authors.forename: Ahmet
authors.initials: A
authors.lastname: Bulut
authors.forename: Okan Zafer
authors.initials: OZ
authors.lastname: Yesilel
authors.forename: Necmi
authors.initials: N
authors.lastname: Dege
authors.forename: Hasan
authors.initials: H
authors.lastname: Icbudak
authors.forename: Halis
authors.initials: H
authors.lastname: Olmez
authors.forename: Orhan
authors.initials: O
authors.lastname: Buyukgungor