Novel crystal modification of <Emphasis Type="Italic">fac</Emphasis>-triamminetrinitrorhodium(III) — β-<Emphasis Type="Italic">fac</Emphasis>-[Rh(NO<Subscript>2</Subscript>)<Subscript>3</Subscript>(NH<Subscript>3</Subscript>)<Subscript>3</Subscript>]

The paper describes the preparation techniques for β-fac-[Rh(NO₂)₃(NH₃)₃]. The complex crystallizes as colorless prisms belonging to the monoclinic crystal system. Crystal data: a = 6.6338(2) Å, b = 11.0627(3) Å, c = 11.5314(3) Å; β = 96.608(1)°, V = 840.64(4) ų, space group P2₁/n, Z = 4, d_calc = 2.308 g/cm³. The structure is molecular and contains neutral complex molecules having the fac configuration. Crystal chemical analysis of the complex in comparison to α-fac-[Rh(NO₂)₃(NH₃)₃] is performed.     

Structure of A Coordination Polymer [Cu(En)<Subscript>2</Subscript>CrO<Subscript>4</Subscript>]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

The crystal structure of [Cu(En)₂CrO₄]_n (En is ethylenediamine) is determined: a = 14.7359(4) Å, b = 9.8083(3) Å, c = 14.2664(4) Å, V = 2061.98(10) ų, space group Cmce, Z = 8, d_x = 1.931 g/cm³. It is demonstrated that the studied phase is isostructural with [Сu(Еn)₂SO₄]_n. A pseudotetragonal copper atom coordination (Cu–N 2.0204 Å and 2.0244 Å, ∠N–Cu–N 84.73°) is completed to distorted octahedral by two oxygen atoms of chromate anions (Cu–O 2.433 Å and 2.380 Å).     

Synthesis, crystal structure and thermal properties of [Co(NH3)5Cl]MO4 (M = Mo, W)

Crystal structures of [Co(NH₃)₅Cl]MoO₄ and [Co(NH₃)₅Cl]WO₄ complex salts are determined by single crystal X-ray diffraction. It is demonstrated for both salts that within the temperature range T = ?123?20°C there is a negative thermal expansion (about 0.26%) towards the c axis of the orthorhombic unit cell (Pnma space group). Thermal properties of the salts are investigated. The phase composition of the products obtained on heating the salts in different gas atmospheres is studied.