Let $\mathbb R$ be the field of real numbers and $\mathbb C$ be the field of complex numbers. Consider the complexification of the real matrix algebra $M_n(\mathbb R)$ that is $\mathbb C\otimes_{\mathbb R}M_n(\mathbb R)$. It is known that $\mathbb C\otimes_{\mathbb R}M_n(\mathbb R)\cong M_n(\mathbb C).$
What is an example of an isomorphism from $\mathbb C\otimes_{\mathbb R}M_n(\mathbb R)$ to $M_n(\mathbb C)?$