Crystal structure and thermal properties of compound K2Zn3(P2O7)2

K2Zn3(P2O7)2was synthesized by solid state reaction and its crystal structure was determined byab initiomethod from powder X-ray diffraction (XRD) data. The title compound was determined to be orthorhombic with space groupP212121,Z=4, and lattice parametersa=12.901(8) Å,b=10.102(6) Å, andc=9.958(1) Å. Values of lattice parameters from 303 to 573 K were measured by temperature-dependent XRD. Thermal expansion coefficientsα0, lattice parameters, and cell volume at 0 K were determined to beα0(a)=1.62327×10−4/K,a0=12.855(4) Å,α0(b)=1.17921×10−4/K,b0=10.070(8) Å,α0(c)=2.62364×10−4/K,c0=9.880(4) Å, andα0(V)=6.599×10−2/K,V0=1278.967(0) Å3. The specific heat equation as a function of temperature was determined to beCp=0.77115+0.00231T−1241.60027T−2−1.4133×10−6T2(J/K g), for temperatures from 198 to 710 K. The melting point estimated from theμ-DTA heating curve is 795 °C.