diff --git a/mkdocs.yml b/mkdocs.yml
index 6158c208ab7b2c0f016fc9baff885aeb3a5bb83a..952a5a806044b9a8e41ae7cde4f0b6c859bc386e 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -34,7 +34,7 @@ nav:
   - Solutions:
     - Einstein model: '1_einstein_model_solutions.md'
     - Debye model: '2_debye_model_solutions.md'
-    - Tight-binding model: '7_Tight-binding_model_sol.md'
+    - Tight-binding model: '7_'
 
 theme:
   name: material
diff --git a/src/7_tight-binding_model_sol.md b/src/7_tight-binding_model_sol.md
new file mode 100644
index 0000000000000000000000000000000000000000..14eeeffa7ca03ef85c7db0f9ac818a97c6569721
--- /dev/null
+++ b/src/7_tight-binding_model_sol.md
@@ -0,0 +1,7 @@
+# Solutions for lecture 7 exercises
+
+### Exercise 1: Lattice vibrations
+
+1.
+Hint: Normal modes have the same function as $$\mathbf{e}_1,\mathbf{e}_2,\mathbf{e}_3$$ in $$\mathbb{R}$$.
+Hint: The lectures concerns atom vibrations 
diff --git a/src/solutions/7_Tight-binding_model_sol.md b/src/solutions/7_Tight-binding_model_sol.md
index a8eb972c87fe3a18336393fc807212ea9d2fec7d..14eeeffa7ca03ef85c7db0f9ac818a97c6569721 100644
--- a/src/solutions/7_Tight-binding_model_sol.md
+++ b/src/solutions/7_Tight-binding_model_sol.md
@@ -4,3 +4,4 @@
 
 1.
 Hint: Normal modes have the same function as $$\mathbf{e}_1,\mathbf{e}_2,\mathbf{e}_3$$ in $$\mathbb{R}$$.
+Hint: The lectures concerns atom vibrations