Aminoguanidinium Fluorozirconates:  Improved Synthesis and Thermal Decomposition of CN₄H₈ZrF₆, CN₄H₈ZrF₆·¹/₂H₂O, CN₄H₈ZrF₆·H₂O, (CN₄H₇)₂ZrF₆, and CN₄H₇ZrF₅

Abstract

Synthesis of the title compounds by present literature methods produces compositional mixtures that are difficult to separate. Controlled temperatures, times, and reactant concentrations produce gram quantities of pure, colorless, transparent crystals. Thermogravimetry and differential scanning calorimetry show that heating to 400 °C in a nitrogen atmosphere causes stepwise decomposition involving first the loss of water (for the hydrated compounds), followed by liberation of HF, then decomposition to ZrF4.

Hydrothermal Synthesis of (C6N2H14)2(UVI2UIVO4F12), a Mixed-Valent One-Dimensional Uranium Oxyfluoride

“…Average equatorial U(1)−F distances are 2.31(8) Å, and average U(3)−F distances are 2.31(7) Å. U(2) is coordinated in a distorted square antiprismatic arrangement of eight F atoms, with a mean bond distance of 2.29(8) Å. Similar [UF 8 ] coordination polyhedra have previously been observed in UFOs that have 8-coordinate uranium such as UFO-9 10 and also in some recently reported zirconium fluoride compounds 2 ORTEP diagrams (probability ellipsoids 50%) showing the local environments of the uranium atoms in UFO-17: (a, top) [UO 2 F 5 ] environment of U(1); (b, middle) The [UF 8 ] environment of U(2); (c, bottom) [UO 2 F 5 ] environment of U(3) including the half-occupied sites F6 and F6‘. …”

Organically Templated Zirconium Fluorides: Hydrothermal Syntheses, Structural Relationships, and Thermal Behavior of (C2H10N2)Zr2F10·H2O and (C4H12N2)ZrF6·H2O

“…Zirconium #uorides illustrate this principle well with molecular, one-, two-, and three-dimensional compounds being known where the coordination number of the Zr(IV) varies from six to eight (13). Aside from fundamental interests, zirconium #uorides are currently under investigation for applications ranging from #ame retardants to NLO materials (14,15). However, the preparative chemistry of these compounds is fraught with a number of synthetic challenges, the most important of which is that most solution-based routes lead to product mixtures (16,17), impeding both the understanding of basic chemical processes and physical property measurements.…”

“…The thermal behavior of zirconium #uorides has been previously investigated to determine both the stability of these compounds and decomposition products (15). The thermal behavior of AU1-6 and AU2-6 were evaluated using di!erential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).…”

Hydrothermal Vanadium Fluoride Chemistry: Four New V3+ Chain Structures

“…However, there has been surprisingly little work in such systems where fluoride represents the only anionic ligand. Several groups have recently begun to explore organically templated metal fluoride chemistry, and a variety of 2D and 3D structures have been reported in, for example, aluminum, − uranium, zirconium, , beryllium, scandium, , and yttrium fluoride systems. A review focusing mostly on amine-templated oligomeric fluoro-anions of Mn, Fe, and Al has also been published …”