Crystal Growth, Room Temperature Crystal Structure and Phase Transitions of KMnPO₄

Abstract

Single crystals of KMnPO4 grown in a KCl flux show ferroelastic domains. The structure was determined on an optically controlled single domain crystal by X-ray diffraction methods. The cell is triclinic with dimensions a = 5.4813(5), b = 8.627(1), c = 8.887(1), in Å, α = 87.73(1)°, β = 89.10(1)°, γ = 88.01(1)°, Vᴍ = 419.6(1) Å3 and Z = 4. The structure is closely related to the stuffed β-tridymite type. DTA experiments between room temperature and 1000 °C and polarized light microscopy observations showed four phase transitions: at 165, 330, 353 and 707 °C.

Structure and magnetic properties of the new phosphate RbMnPO4

“…Mn2 is located in a tetrahedral site connected to 3 P2O 4 and 1 P2O 4 tetrahedra by sharing corner. The average Mn2-O distance is equal to 2.00Å and this value is slightly lower than the average value of 2.066Å found in KMnPO 4 [3]. The structure of RbMnPO 4 is more distorted than the structure of KMnPO 4 .…”

“…Usually the zeolite frameworks consist of a net of corner-shared tetrahedral sites filled by Al 3+ , Ga 3+ , Si 4+ , P 5+ or V 5+ , the originality of the series ABPO 4 is the large amount of divalent transition metal like Co 2+ and Mn 2+ in the zeolite framework. In the case of the cobalt and manganese phosphates RbCoPO 4 [1], CsCoPO 4 [2], KMnPO 4 [3] and CsMnPO 4 [4] the transition metals are located in distorted tetrahedral sites. Several authors have succeeded to prepare two new cobalt phosphates with zeolite type-structure with sodium atoms instead of rubidium or caesium atoms [5,6].…”

Polyanionic Compounds for Potassium‐Ion Batteries

“…The simple alternative idea is the application of K‐containing phosphates such as KFePO 4 and KMnPO 4 . Although the synthesis and crystal structure of KFePO 4 and KMnPO 4 have been reported, the electrochemical properties of KFePO 4 and KMnPO 4 have not been reported yet. Therefore, we synthesized KFePO 4 and KMnPO 4 via the solid‐state method as described in supporting information and investigated their electrochemical performances.…”

“…Furthermore, we find redox‐active Fe and Mn‐based polyanionic compounds as potassium insertion host. Although K‐containing polyanionic compounds like KFePO 4 , KMnPO 4, and K 2 FeP 2 O 7 have been reported, there are no studies on electrochemical potassium insertion/extraction into these compounds.…”

Crystal Structures and Crystal Chemistry of AgXPO4(X=Be, Zn)

“…The latter has also been observed to undergo an unusual phase transformation at 666°C from a low-temperature hexagonal phase to a high-temperature monoclinic phase (22) and, on the basis of X-ray powder data, the monoclinic phase has been described as beryllonite-like and the hexagonal phase as nepheline-like (for the latter, in spite of some significant discrepancies between the observed and calculated X-ray intensities). As part of an ongoing study of the crystal chemistry and polymorphism of tetrahedral framework compounds which are tridymite derivatives [e.g., (4) and (6)], the crystal structures of -AgZnPO (low ¹ ), -AgZnPO (high ¹ ), and AgBePO have been determined by single-crystal X-ray diffraction. These structures are described here together with a discussion of the polymorphism in AgZnPO .…”