Description:
<jats:title>Abstract</jats:title><jats:p>Eu<jats:sub>2</jats:sub>SiO<jats:sub>3</jats:sub>Cl<jats:sub>2</jats:sub> and Eu<jats:sub>5</jats:sub>SiO<jats:sub>4</jats:sub>Cl<jats:sub>6</jats:sub> were prepared by reaction of EuCl<jats:sub>2</jats:sub> with EuSiO<jats:sub>3</jats:sub> and Eu<jats:sub>2</jats:sub>SiO<jats:sub>4</jats:sub>, respectively, Sr<jats:sub>2</jats:sub>SiO<jats:sub>3</jats:sub>Cl<jats:sub>2</jats:sub>: Eu<jats:sup>2+</jats:sup> from mixtures of SrCO<jats:sub>3</jats:sub>, Eu<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>, SrCl<jats:sub>2</jats:sub> · 6H<jats:sub>2</jats:sub>O and SiO<jats:sub>2</jats:sub> under reducing conditions. The crystal structures of Eu<jats:sub>2</jats:sub>SiO<jats:sub>3</jats:sub>Cl<jats:sub>2</jats:sub> [a = 1118.7(5), c = 952.6(1) pm, tetragonal, I4/m, Z = 8, R = 3.3, R<jats:sub>w</jats:sub> = 3.0%] and Eu<jats:sub>5</jats:sub>SiO<jats:sub>4</jats:sub>Cl<jats:sub>6</jats:sub> [a = 900.4(1), b = 1401.7(2), c = 1112.3(2) pm, β = 103.51(1)°, monoclinic, C2/c, Z = 4, R = 3.6, R<jats:sub>w</jats:sub> = 2.6%] were determined from four‐circle diffractometer data and compared with related compounds. The luminescence properties were investigated at 300 K and at 4.2 K; all compounds show intense bluish‐green photoluminescence. Sr<jats:sub>2</jats:sub>SiO<jats:sub>3</jats:sub>Cl<jats:sub>2</jats:sub>:Eu<jats:sup>2+</jats:sup> shows thermoluminescence.</jats:p>