A new modification of thallium chromate related to the β‐K2SO4 family

The title structure is a new modification of Tl₂CrO₄. There are four independent Tl⁺ cations and two [CrO₄]²⁻ anions in the structure. It is closely related to the already known modification, which belongs to the β‐K₂SO₄ family with two independent cations and one anion. In both modifications, the cations and anions are situated on crystallographic mirror planes. The volume of the asymmetric unit of the title structure is ∼0.4% smaller than that of the known modification belonging to the β‐K₂SO₄ family. The other difference between the two modifications is seen in the environment of the cations. In the title structure, none of the Tl⁺ cations is underbonded, in contrast with the modification isostructural with β‐K₂SO₄. In the β‐K₂SO₄ family with simple cations, underbonding of one of the constituent cations is typical. The dependence of the unit‐cell parameters on temperature does not indicate a phase transition in the interval 90–300 K.