Structural investigations of two bismuth‐ammonium condensed phosphates: BiHNH 4 P 3 O 10 and BiNH 4 (PO 3 ) 4

Chemical preparations and crystal structures are described for two new bismuth salts: BiHNH 4 P 3 O 10 and BiNH 4 (PO 3 ) 4 . The first one is a new type of tripolyphosphate, while the second one, a long chain polyphosphate, is isostructural with RbNd(PO 3 ) 4 and some other M I Ln(PO 3 ) 4 compounds. BiHNH 4 P 3 O 10 is triclinic, P 1 , with a = 7.032(8), b = 7.696(4), c = 8.659(3) Å, α = 106.20(4), β = 105.86(4), γ = 82.78(4)°, Z = 2, V = 432.3 Å 3 , Dx = 3.694. BiNH 4 (PO 3 ) 4 is monoclinic, P2 1 /n, with a = 10.925(9), b = 9.034(8), c = 10.438(9) Å, β = 106.18(4), Z = 4, V = 989.4 Å 3 , Dx = 3.644. The crystal structure of BiHNH 4 P 3 O 10 has been solved by using 4253 independent reflexíons with a final R value of 0.056. The unit cell contains two P 3 O 10 5− groups related by an inversion center while bismuth atoms in a eightfold coordination build infinite chains of edge‐sharing BiO 8 polyhedra running parallel to the a axis. The crystal structure of BiNH 4 (PO 3 ) 4 has been solved using 4330 independent reflexions with a final R value of 0.047. Infinite (PO 3 ) ∞ chains spread along the [101] direction, alternating with isolated BiO 8 polyhedra.