Crystal structure of 1-methyl-2-quinolonium dihydrogen arsenate

Abstract

This compound crystallises with four 4QH₃AsO₄(Q = 1-methyl-2-quinolone) molecules in a cell of space group Pna2₁, with a= 18·928, b= 12·717 and c= 4·875 Å. The structure has been solved and refined to R= 12% for 1281 independent X-ray reflexions. The H₂AsO₄^– groups are linked into infinite helical chains by hydrogen bonds. The quinolonium residues (QH⁺) are attached, laterally, to the helix by hydrogen bonds from the protonated carbonyl group, with O–H ⋯ O = 2·495 Å. In discrete XO₄-ions, the sum of the four X–O bond-lengths is approximately constant. The sum of the As–O distances in this crystal is 6·74 Å, which is within the range 6·6–6·8 Å found in other arsenates.