A single phased white light emitting phosphors K2Ca1-x-yP2O7:xEu(2+),yMn(2+) were synthesized by solid state reaction method. The Effective energy transfer occurs in this phosphor due to the large spectral overlap between the emission of Eu2+ and the excitation of Mn2+. The emission hue of K2Ca1-x-yP2O7:xEu(2+), yMn(2+) from blue to white light can be obtained by tuning the Eu2+/Mn2+ content ratio. The energy transfer mechanism from Eu2+ to Mn2+ in this phosphor was carefully investigated and demonstrated to be via the dipoleequadrupole interaction. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.