Paper Title
Redetermination Of The Crystal Structure Of Copper Selenite, Cu2SeO4

Abstract
The title compound, copper selenite, Cu2SeO4, which was usually used as a catalyst of the Kjeldahlnitrogen determination1, was synthesized using a hydrothermal methodat 443 K and its crystal structure was redetermined based on modern CMOS (complementary metal oxide silicon) data from single-crystal X-ray diffraction at room temperature. The title compound crystallizes in the cubic chiral space group P213 with a Flack parameter of 0.014 (7). The structure consists of {CuO5} square pyramids, {CuO5} trigonal bipyramids and {SeO3} trigonal pyramids sharing edges to build up a three-dimensional network where the lone pairs of electrons on SeIV are accommodated in void regions in the structure, which correlated with the previously reported structure model synthesized by transport method at higher temperature (673-723 K)(Meunier &Bertaud, 19762).All atoms in the crystal structure were located with lattice parameters, fractional coordinates and absolute structure determined to a much higher precision. The proposed structural model was validated by bond-valence-sum calculations. Keywords: Crystal structure, Copper(II), Metal oxide, Selenium, Selenite