Crystal Structure, Vibrational Spectra and Activation of BaCa(P 4 O 12 ) with Eu 2+ Compared with β‐Sr(PO 3 ) 2 :Eu

The polyphosphates β‐Sr(PO 3 ) 2 and BaCa(PO 3 ) 4 were doped with Eu 2+ , BaCa(PO 3 ) 4 was structurally characterised for the first time. Both phosphors were analysed by fluorescence spectroscopy. β‐Sr(PO 3 ) 2 :Eu and BaCa(PO 3 ) 4 :Eu were found to emit blue light at 424 nm and 418 nm, respectively, with a broader emission band compared with α‐Sr(PO 3 ) 2 :Eu. Both phosphors can be excited at 330 nm, i.e. an UV‐LED emission. The crystal structure of BaCa(PO 3 ) 4 has been determined based on single‐crystal data [ P 2 1 / n , Z = 4, a = 723.00(11), b = 917.05(19), c = 1524.7(2) pm, β = 90.995(12)°, R1 = 0.050, wR2 = 0.099, 1748 reflections, 164 parameters]. BaCa(PO 3 ) 4 is not homeotypic with β‐Sr(PO 3 ) 2 and α‐Sr(PO 3 ) 2 but isotypic with BaCd(PO 3 ) 4 . The vibrational spectra of BaCa(PO 3 ) 4 are also presented and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)