SrBr2, or Strontium Bromide, is considered a polar compound. To understand why, we need to look at its molecular structure and the nature of the bonds within it.
Strontium, a Group 2 element, has a tendency to lose two electrons to form a cation (Sr2+), while bromine, a Group 17 element, tends to gain one electron to form an anion (Br–). In SrBr2, there are two bromine atoms bonded to one strontium atom. The bonds formed between strontium and bromine are ionic in nature due to the significant difference in their electronegativities. This ionic character is a primary reason for the polarity of SrBr2.
As for its shape, SrBr2 adopts a crystalline structure. In the solid state, the ionic lattice that forms is generally represented in a geometric arrangement. The individual Sr2+ and Br– ions will occupy specific positions in a three-dimensional lattice, maximally optimizing the attraction and repulsion between them. This organized structure does not have a ‘shape’ in the way molecular compounds do, but if one were to consider the ionic dimensions, the arrangement would resemble a cubic lattice due to the packing of ions.
In summary, SrBr2 is polar due to its ionic bonds, and its shape is best described as a crystalline lattice in the solid state.