Structure of molecular adducts of inorganic salts. VIII. Thiourea complexes of cadmium nitrate

Abstract

In the system Cd(NO3)2-tu-H2O, tu = thiourea, the structures of three Cd(NO3)2 · ntu (n=2, 4) addition compounds were carried out. Monoclinic Cd(NO3)·2tu, space group P21/n, a = 4.267(1)Å, b = 11.956(1) Å, c = 11.330(1) Å, β = 100.22(6)°. The crystal structure is built up of neutral [Mtu2 ·(NO3)2] centrosymmetric complexes. The two polymorphic modifications when n = 4 coexist under ambient conditions. They are both monoclinic, space group P21/c, with cell parameters are a=21.380(3)Åβ =5.975(1) Å, c = 17.531(4) Å, β = 122.56(2)° for (I) and a = 12.811(3) Å, b= 9.157(1)Å, c = 15.770(2)Å, β = 91.20(1)° for (II). Their structures consist of complex [Mtu4] 2 + cations and NO3 - anions, linked through extensive networks of weak hydrogen bonds which hold the structural units together.