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Preparation, Single Crystal Structure Analysis, and Thermal Behaviour of the Acidic Mercury(I) Phosphate (Hg 2 ) 2 (H 2 PO 4 )(PO 4 )
Author(s) -
Weil Matthias
Publication year - 2000
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200008)626:8<1752::aid-zaac1752>3.0.co;2-1
Subject(s) - chemistry , crystallography , crystal structure , microcrystalline , oxygen atom , phosphate , single crystal , hydrogen bond , stereochemistry , molecule , organic chemistry
Yellowish single crystals of acidic mercury(I) phosphate (Hg 2 ) 2 (H 2 PO 4 )(PO 4 ) were obtained at 200 °C under hydrothermal conditions in 32% HF from a starting complex of microcrystalline (Hg 2 ) 2 P 2 O 7 . Refinement of single crystal data converged at a conventional residual R[F 2 > 2σ(F 2 )] = 3.8% (C2/c, Z = 8, a = 9.597(2) Å, b = 12.673(2) Å, c = 7.976(1) Å, β = 110.91(1)°, V = 906.2(2) Å 3 , 1426 independent reflections > 2σ out of 4147 reflections, 66 variables). The crystal structure consists of Hg 2 2+ ‐dumbbells and discrete phosphate groups H 2 PO 4 – and PO 4 3– . The Hg 2 2+ pairs are built of two crystallographically independent Hg atoms with a distance d(Hg1–Hg2) = 2.5240(6) Å. The oxygen coordination sphere around the mercury atoms is asymmetric with three O atoms for Hg1 and four O atoms for Hg2. The oxygen atoms belong to the different PO 4 tetrahedra, which in case of H 2 PO 4 ‐groups are connected by hydrogen bonding. Upon heating over 230 °C, (Hg 2 ) 2 (H 2 PO 4 )(PO 4 ) condenses to (Hg 2 ) 2 P 2 O 7 , which in turn disproportionates at higher temperatures into Hg 2 P 2 O 7 and elemental mercury.