Copper(II) hypophosphite: the α- and β-forms at 270 and 100 K, and the γ-form at 270 K

Abstract

Copper(II) hypophosphite has been shown to exist as several polymorphs. The crystal structures of monoclinic alpha-, orthorhombic beta- and orthorhombic gamma-Cu(H(2)PO(2))(2) have been determined at different temperatures. The geometry of the hypophosphite anion in all three polymorphs is very close to the idealized one, with point symmetry mm2. Despite having different space groups, the structures of the alpha- and beta-polymorphs are very similar. The polymeric layers formed by the Cu atoms and the hypophosphite ions, which are identical in the alpha- and beta-polymorphs, stack in the third dimension in different ways. Each hypophosphite anion is coordinated to three Cu atoms. On cooling, a minimum amount of contraction was observed in the direction normal to the layers. The structure of the polymeric layers in the gamma-polymorph is quite different. There are two symmetry-independent hypophosphite anions; the first is coordinated to two Cu atoms, while the second is coordinated to four Cu atoms. In all three polymorphs, the Cu atoms are coordinated by six O atoms of six hypophosphite anions, forming tetragonal bipyramids; in the alpha- and beta-polymorphs, there are four short and two long Cu-O distances, while in the gamma-polymorph, there are four long and two short Cu-O distances.

Hexaaquanickel(II) bis(hypophosphite)

“…The hypophosphite anions do not coordinate to the Ni II cation. According to previously reported data, the average MÐO distance for hexahydrated bivalent metal hypophosphites is 2.05 (1) A Ê for magnesium(II) (Galigne  & Dumas, 1973), 2.074 (3) A Ê for cobalt(II) and 2.055 (2) A Ê for cobalt(II)/ nickel(II) (Kuratieva et al, 2002). The average NiÐO distance in the present study is 2.045 (7) A Ê .…”

“…This paper presents the results of the single-crystal Xray diffraction analysis of hexaaquanickel(II) bis(hypophosphite), [Ni(H 2 O) 6 ](H 2 PO 2 ) 2 . The calculated powder pattern of this compound, (I), is in good agreement with the experimental powder pattern, but is different from those of hexaaquacobalt(II) bis(hypophosphite) and hexaaquacobalt(II)/ nickel(II) bis(hypophosphite) (Kuratieva et al, 2002).…”

“…Studies of hexaaquametal(II) bis(hypophosphite)s have been reported previously by Ferrari & Colla (1937), Pe  drazuela et al (1953), Galigne  & Dumas (1973) and Kuratieva et al (2002). This paper presents the results of the single-crystal Xray diffraction analysis of hexaaquanickel(II) bis(hypophosphite), [Ni(H 2 O) 6 ](H 2 PO 2 ) 2 .…”

“…The powder pattern for this compound was reported previously by Ferrari & Colla (1937) and the compound was indexed as a cubic system with an a cell parameter of 10.30 A Ê . This mismatch has been discussed by Kuratieva et al (2002).…”

NaCo(H2PO2)3: Crystal structure and physical study

“…We found reports on several hypophosphites of transition metals and lanthanides [1e7], and few mixed hypophosphites: NaCa(H 2 PO 2 ) 2 [8] and Co 0.5 (H 2 O) 6 Ni 0.5 (H 2 PO 2 ) 2 [9]. Several other simple phases are known, e.g., AH 2 PO 2 , A ¼ K, Rb, Cs [10], Mg(H 2 O) 6 (H 2 PO 2 ) 2 [11], Mn(H 2 PO 2 ) 2 .H 2 O [12], Co(H 2 O) 6 (H 2 PO 2 ) 2 [9,13], and Cu(H 2 PO 2 ) 2 [14]. Some powder crystallographic data are also known: M(H 2 PO 2 ) 2, Co(H2PO2)2.0.53H2O [15], and VO(H 2 PO 2 ) 2 .H 2 O [16].…”