Silver trimagnesium phosphate bis(hydrogenphosphate), AgMg₃(PO₄)(HPO₄)₂, with an alluaudite-like structure

Abstract

Key indicators: single-crystal X-ray study; T = 296 K; mean (P-O) = 0.001 Å; disorder in main residue; R factor = 0.026; wR factor = 0.075; data-to-parameter ratio = 25.6.The title compound, AgMg 3 (PO 4 )(HPO 4 ) 2 , which has been synthesized by the hydrothermal method, has an alluauditelike structure which is formed by edge-sharing MgO 6 octahedra (one of which has symmetry 2), resulting in chains linked together by phosphate groups and hydrogen bonds. The three-dimensional framework leads to two different channels along the c axis, one of which is occupied by Ag + ions with a square-planar coordination. The Ag + ions are disordered over two sites in a 0.89 (3):0.11 (3) ratio. The OH groups, which point into the other type of channel, are involved in strong O-HÁ Á ÁO hydrogen bonds. The title compound is isotypic with the compounds AM 3 H 2 (XO 4 )(HXO 4 ) 2 (A = Na or Ag, M = Mn, Co or Ni, and X = P or As) of the alluaudite structure type. Related literature

Synthesis, Crystal Structure, and Properties of the Alluaudite-Type Vanadates Ag2–xNaxMn2Fe(VO4)3

“…Therefore, we believe that the preparation of alluaudite vanadates would be more successful using larger A and A ′ cations such as Ag ( R ionic = 1.28 Å) which could be gradually replaced by sodium. In this context, it is worth mentioning that, based on the Inorganic Crystal Structure Database (ICSD), only 14 alluaudite compounds containing silver cations have been reported, − and all of them are phosphates and arsenates (Table S1).…”

Synthesis and crystal structure of two new phosphates with Alluaudite type structure: (M, Mn)3Fe(PO4)3 (M= Ca, Cd)

“…Récemment, un grand nombre de composés phosphatés appartenant à ce type structural ont été élaborés par les chercheurs de notre laboratoire. Nous pouvons citer, à titre d'exemple, AgMg 3 (PO 4 )(HPO 4 ) 2 [13], NaMg 3 (PO 4 )(HPO 4 ) 2 [14], Na 2 Co 2 Fe(PO 4 ) 3 [15] Atome U11 U22 U33 U12 U13 U23 Fe1/Mn1* 0,0102 (1) 0,0079 (1) 0,0113 (1) 0,00167 (7) 0,0061 (9) 0,002 (7) Fe1/Mn1 0,0076 (1) 0,0079 (1) 0,0076 (1) 0,0016 (6) 0,0041 (7) 0,0018 (6) Ca1/Mn2* 0,0128 (2) 0,0191 (2) 0,0148 (2) 0,000 0,0096 (2) 0,000 Cd1/ Mn2 0,0105 (1) 0,0129 (1) 0,0111 (1) 0,000 0,0075 (9) 0,000 Ca2* 0,0051 (8) 0,0168 (1) 0,0086 (9) 0,000 0,0013 (7) 0,000 Cd2 0,0029 (7) 0,0253 (1) 0,0078 (7) 0,000 0,0002 (6) 0,000 Ca3* 0,0157 4…”