Qualitative and quantitative morphological study on α and β phases of ammonium pentaborate tetrahydrate

Abstract

A qualitative and quantitative morphological study on the α and β phases of ammonium pentaborate tetrahydrate has been carried out. Crystals of the two phases were obtained by slow evaporation from aqueous solutions. Usually the α phase was obtained with {101}; {01}; {011} and {110} as crystal forms, a high percentage of the crystals (99%) were twins, with a twofold axis parallel to c as the twin law. When MgCl2.6H2O was added to the solution, the β phase was obtained as prismatic crystals elongated along [10] with {111}, {11 } and {001} as crystal forms. Generally, these crystals were also twins, with a twofold axis parallel to [110] as twin law. A qualitative and quantitative morphological study showed the α‐phase crystals to have the theoretical growth forms, while the crystal forms of the β phase were explained by the presence in the solution of (H2O)6Mg2+ and Cl− ions.

Growth, structural, optical, thermal and mechanical properties of ammonium pentaborate single crystal

“…At room temperature, APB crystal belongs to monoclinic system and the cell parameters are presented in Table 1 which are well matched with the reported values [5].…”

“…The elastic constants [3] and optical behaviour of ammonium pentaborate under linear and hydrostatic stresses [4] were reported. Solans et al [5] have reported the morphological studies of ␣-and ␤-phases of APB. In the present investigation, the growth, structural, mechanical, and thermal properties of ␣-phase APB are reported.…”

Crystal structures of ethylenediaminetetraacetato metal complexes. III. Hexaaquamagnesium(II) aquaethylenediaminetetraacetatocadmium(II) trihydrate, [(H2O)6Mg(C10H12N2O8)(H2O)Cd]n.3nH2O

“…These coordinating atoms lie at the vertices of a pentagonal bipyramid. This coordination is similar to those obtained in other heptacoordinated EDTA complexes (Richards, Pedersen, Silverton & Hoard, 1964;Lind, Hamor, Hamor & Hoard, 1964;Stezowski, Countryman & Hoard, 1973;Passer et al, 1977;Solans et al, 1983b) which changes from the monocapped trigonal prism to the pentagonal bipyramid.…”

“…The average Mg--O bond length and O-Mg-O bond angle are 2.80 A and 91.3 °, values similar to those obtained in (HEO)6Mg(EDTA)(HEO)Mg.3H20 (Passer et al, 1977) or [(H20)4Mg(EDTA)Zn],.2nH20 (Solans et al, 1983a (4) 7662 (7) 770 (16) -1352 (18) 2.2 (4) W (5) 5577 (5) 413 (16) 7465 (16) 2-1 (3) W (6) 1203 (7) 376 (18) 2487 (19) 3-4 (5) W (7) 555 (7) 7300 (18) 832 (18) (8) 6865 (4) 8885 (11) 3129 (11) 1.9 (3) C (9) 7135 (5) 10478 (14) 4426 (15) 2.0 (4) C (10) 7213 (6) 11892 (14) 3355 (16) 2.9 (5) N (11) 7736 (4) 11179 (10) 2203 (11) 1.6 (3) O (12) 6310 (3) 7269 (10) -284 (10) 2.1 (3) C (13) 5908 (5) 6905 (15) 745 (15) 2.4 (4) O (14) 5321 (3) 7479 (9) 496 (10) 1.9 (3) C (15) 6149 (4) 9115 (12) 2590 (15) 1.8 (4) O (16) 8056 (4) 6855 (12) 2994 (11) 2-6 (4) C (17) 7741 ...…”

Sodium ion complexes with ethylenediaminetetraacetic acid

“…Crystal structure studies of edta complexes with Na have been carried out (Solans, Font-Altaba & Garcia-Oricain, 1984;Nassimbeni, Wright, van Niekerk & MacCullum, 1979;Templeton, Templeton, Zalkin & Ruben, 1982;Templeton, Templeton & Zalkin, 1985;Solans, Gali, Font-Altaba, Oliva & Herrera, 1988;Lee, 1967;Porai-Koshits, Novozhilova, Polyniva, Filippova & Martynenko, 1973;Pozhidaev, Polynova, Porai-Koshits & Dudakov, 1974), but always on complexes containing a second metal. It is the second metal that is coordinated to the edta ligand in all the crystal structures determined.…”