Structure and magnetic properties of Ca14MnP11

The compound Ca14MnP11 crystallizes in the Ca14AlSb11 structure type with the tetragonal space group image (image) and lattice parameters of image, image at 90 K. The structure consists of MnP49− tetrahedron, P37− trimer, 4 P3− isolated anions and 14 Ca2+ cations. Similar to other compounds of this structure type containing phosphorous, the P37− trimer has a central P atom that is best modeled in the structure as being equally split between two sites. In addition, there is no additional distortion of the manganese-containing tetrahedron compared with the main group analog, Ca14GaP11, suggesting that the Mn oxidation state is Mn2+. Temperature-dependent magnetic susceptibility shows that the compound is paramagnetic over the entire temperature range measured (2–300 K). The data can be fit with a modified Curie–Weiss law and provide an effective magnetic moment of 5.80 (2) B.M. with a Weiss constant of −2.13(2) K and image. This moment is significantly higher than those measured for any of the Mn-containing analogs and is consistent with Mn2+. This result will be discussed in light of the electron counting scheme for Mn compounds of the Ca14AlSb11 structure-type.