Preparation of anhydrous aminoguanidinium(2+) hexauorozirconate, CN 4 H 8 ZrF 6 , shown previously to satisfy the structural criteria for ferroelectricity [Abrahams et al. (1996). Acta Cryst. B52, 806±809], generally results in the co-formation of a series of related¯uorozirconates.

Analysis of the atomic arrangement in anhydrous aminoguanidinium hexafluorozirconate, CN4H8ZrF6, reported by Bukvetskii, Gerasimenko & David­ovich [Koord. Khim. (1990), 16, 1479–1484], led to the prediction that it is a new ferroelectric [Abrahams, Mirsky & Nielson (1996). Acta Cryst. B52, 806–809]. Initial attempts to verify the prediction were inconclusive because of the variety of closely related materials produced under the original preparation conditions. Clarification of these conditions led to the formation of pure CN4H8ZrF6 and the growth of single crystals with dimensions as large as 7 × 7 × 2 mm. Highly reproducible calorimetric and dielectric permittivity anomalies reveal the Curie temperature Tc = 383 (1) K. At this temperature, the heat capacity Cp exhibits an entropy change of 0.7 (1) J mol−1 K−1, while the relative permittivity ɛr exhibits an inflection and the dielectric loss a distinct peak; the dielectric anomaly at Tc is observed only at the lowest (0.1–1 kHz) frequencies used. Dielectric hysteresis is demonstrable at 295 K under the application of ∼1 MV m−1 alternating fields and remains observable at all T < Tc but not at T≥Tc; the prediction of ferroelectricity is hence confirmed. The value of the spontaneous polarization Ps is 0.45 (9) × 10−2 C m−2 at 298 K, with piezoelectric coefficient d33 = 1.9 (5) pC N−1 and pyroelectric coefficient p3 = 4 (1) µC m−2 K−1. Tilts of less than ∼11° by the two symmetry‐independent CN4H ions, combined with rotations of ∼20° or less by the N—NH3 and C—(NH2)2 groups about the central C—N bond in each cation, as all H atoms rotate into or become symmetrically distributed about the planes at z = 0 or ½, allow them to conform to mirror symmetry via polar atomic displacements of ∼0.4 Å or less by N or C, and of 0.7 Å or less by H. Corresponding displacements of less than 0.08 Å within the two symmetry‐independent ZrF anions also result in mirror symmetry, satisfying the structural criteria required for the development of ferroelectricity.

Two technologies were evaluated for daily manure removal in shallow, sloped pits in swine finishing facilities. The criteria included cleaning ability, initial cost, and water usage. One system selected for the trial was mechanical and one was liquid-based. Preliminary results of the scraper system have shown clean pit floor and side walls. The frequency of scraping has been reduced to several times per day and twice after a weekend. Challenges of the system include cleaning the front 0.45 m (18") along the wall and using water to assist the drainage of manure. Results of the tip tank have shown a 4 gallon per pig recycle water usage per day. Flushability of the solids and development of sufficient head were factors in this 3 design. Both systems were automated to lessen human intervention and designed to allow the recycle pumps to be shut down at night.