Formation of Two Types of Plate Crystals in the Reaction of Ytterbium(0) and Ytterbium(III) Oxide with (1-Hydroxyethylidene)Diphosphonic Acid

Abstract

The interaction of ytterbium(0) shavings with one equivalent of (1-hydroxyethylidene)diphosphonic acid (H₄L) in aqueous medium leads to the production of a sparingly soluble hydrate, (1-hydroxyethylidene)ytterbium(III) diphosphonate monohydrate YbHL·H₂O. According to the scanning electron microscopy data, the compound has been precipitated from the aqueous solution as thin plate crystals with a length up to 7 μm and a width up to 2 μm. Their thickness can reach 0.3–0.5 μm. The plates are practically not bended; the height difference is 5–7 nm on a flat part. In a reaction with ytterbium(III) oxide Yb₂O₃ the compound YbHL·H₂O has also been obtained. The YbHL·H₂O crystals precipitating from the aqueous solution are lamellar; their shape differs in appearance compared to the crystals obtained from metal. The plates are thinner, more curved, packed in piles, approaching a square with a side of 5–7 μm in shape. According to atomic force microscopy, the plate thickness is 1 μm, the average roughness of smooth surface is Ra = 27 nm (arithmetic average deviation), RMS = 35 nm (standard deviation). During interacting with 2-aminoethanol, (1-hydroxyethylidene)ytterbium(III) diphosphonate monohydrate does not pass into solution, but gives a viscous sol, after drying of which the YbHL·H₂NCH₂CH₂OH·4H₂O complex is obtained. The obtained compounds have been studied by elemental analysis, infrared spectroscopy, scanning electron and atomic force microscopy, X-ray phase analysis.