Transition-Metal Monofluorophosphate Ba₂M₂(PO₃F)F₆ (M = Mn, Co, and Ni): Varied One-Dimensional Transition-Metal Chains and Antiferromagnetism

Open-Framework Iron Fluoride Phosphates Based on Chain, Trinuclear, and Tetranuclear Chain FeIII Building Units: Crystal Structures and Magnetic Properties

“…Four normal P-O/F bond distances range from 1.527(4) to 1.539(4) Å. However, the P2 atoms are coordinated tetrahedrally by three oxygen atoms and one terminal F atom with P–O bond distances of 1.514(4)–1.523(4) Å and one elongated P–F bond length of 1.559(4) Å, consistent with previously reported values for this structural unit. ,,, …”

“…A microwave frequency of ν 4) Å, consistent with previously reported values for this structural unit. 11,13,22,23 The structure of K 2 Fe(PO 2.5 F 1.5 ) 2 F 2 (II) consists of polyhedral KF 3 O 2 (O/F) 2 , octahedral trans-FeO 4 F 2 , and tetrahedral PO 2.5 F 1.5 building units (Figure 2a). The structure can be described as {Fe(PO 2.5 F 1.5 ) 2 F 2 } 2− chains oriented along the a direction in a rectangular plane grouped in a p2gg manner, formed by each trans-FeO 4 F 2 octahedral that is connected by two PO 2.5 F 1.5 tetrahedra via oxygen atoms (see Figure 2b), isolated by the KF Compound III can be regarded as a {Fe 3 (PO 4 )(PO 3 F) 2 F 4 } 3− macroanionic network, whose charge neutrality is balanced with K + ions (Figure 3a).…”

“…Our group successfully improved the fluoride-rich hydrothermal route to control redox reactions or promote crystal growth by adjusting the pH of hydrothermal solutions. − Here, we report the synthesis and characterization of new open-framework iron fluoride-fluorophosphates, KFe 2 (PO 3 F) 2 F 3 ( I ), K 2 Fe­(PO 2.5 F 1.5 ) 2 F 2 ( II ) K 3 Fe 3 (PO 4 )­(PO 3 F) 2 F 5 ( III ), and K 3 Fe 4 (PO 4 ) 2 F 9 ( IV ), using not only hydrazine monohydrate but also alkali metal hydroxide as starting materials to balance phosphoric and fluorophosphoric acids, enabling the growth of high-quality single crystals under mild conditions. IV is geared toward geometrically frustrated magnets (GFMs), in which the geometry of the magnetic lattice precludes the simultaneous minimization of the energy of all antiferromagnetically interacting spins.…”

Cycloidal Magnetic Order Promoted by Labile Mixed Anionic Paths in M2(SeO3)F2 (M = Mn2+, Ni2+)

“…The magnetic susceptibility of Mn 2 SeO 3 F 2 is similar to that reported in ref . In a few words, it shows a ZFC/FC divergence below T N = 26.1(1) K. The Curie–Weiss fit above 100 K results in a Curie–Weiss temperature (Θ CW ) = −71.0(1) K and μ eff = 5.88(2) μ B per Mn 2+ (see Figure S9, vs 6.06 μ B /Mn 2+ in ref ), close to the spin-only value of 5.92 μ B ( S = 5/2, L = 0, g = 2), similarly to other Mn 2+ fluorophosphates such as (NH 4 )­Mn 3 (PO 3 F) 2 (PO 2 F 2 )­F 2 and Ba 2 Mn 2 (PO 3 F)­F 6 Figure b shows the isothermal magnetization M ( H ) at various temperatures, which reaches M 9T ≈ 1.17 μ B /Mn 2+ at 2.4 K. The aligned moment for our sample is also higher than that reported for polycrystals ( M 12T ≈ 0.84 μ B /Mn 2+ ) .…”

MIO3F (M = Co and Ni): Magnetic Iodate Fluorides with Zigzag Chains

“…In addition, absorption bands at 472 cm –1 for 1 and 497 cm –1 for 2 are both assigned to δ s (I–O) vibrations . In addition, the remaining ν s (M–O) vibrations, which are usually found around 500 cm –1 , possibly overlap with δ s (I–O) vibrations. , Moreover, the broad absorptions around 3436 and 1630 cm –1 may be from water molecules absorbed in air for both compounds. , …”